https://www.causeweb.org/wiki/chance/api.php?action=feedcontributions&user=PaulAlper&feedformat=atomChanceWiki - User contributions [en]2022-01-20T18:03:36ZUser contributionsMediaWiki 1.34.0https://www.causeweb.org/wiki/chance/index.php?title=Chance_News_74&diff=13603Chance News 742011-06-15T23:12:57Z<p>PaulAlper: /* Overdiagnosed, overtreated */</p>
<hr />
<div>==Quotations==<br />
"The government are very keen on amassing statistics. They collect them, add them, raise them to the nth power, take the cube root and prepare wonderful diagrams. But you must never forget that every one of these figures comes in the first instance from the village watchman, who just puts down what he damn pleases."<br />
<br />
<div align=right>Sir Josiah Charles Stamp [1880-1941]</div align=right><br />
As quoted by Howard Wainer, in [http://press.princeton.edu/titles/8863.html <i>Picturing the Uncertain World</i>]<br />
Princeton University Press, 2009, p. 23. The above observation is by no means dated, as shown by the following exerpt from p. 24:<br />
<br />
"The term curbstoning describes a practice that is widespread enough to warrant inclusion in the <br />
glossary of ''The 2000 Census: Interim Assessment'', which defines it as 'The practice by which a census enumerator fabricates a questionnaire for a residence without actually visiting it.' "<br />
<br />
Submitted by Paul Alper<br />
<br />
----<br />
"So when I hear scientists say, 'The data speak for themselves,' I cringe. Data never speak. And data generally and most often are politically and socially inflected."<br />
<br />
<div align=right>Andrew J. Hoffman, Professor of Sustainable Enterprise, University of Michigan</div align=right><br />
<br />
As quoted in [http://green.blogs.nytimes.com/2011/04/09/taking-on-climate-skepticism-as-a-field-of-study/?hpw Q. and A.: Taking On Climate Skepticism as a Field of Study],<br />
Green Blog, ''New York Times'', 9 April 2011<br />
<br />
Submitted by Bill Peterson<br />
<br />
==Forsooth==<br />
<br />
==Overdiagnosed, overtreated==<br />
<br />
Obviously, the sun revolves around the earth, the harmonic series converges and the earth is flat. Likewise, the prevailing medical paradigm is: early screening leads to early intervention resulting in improved medical outcomes. Completely plausible and believed by most patients and medical practitioners alike. If you are one of the believers then you ought to read H. Gilbert Welch’s ''Overdiagnosed: Making People Sick In The Pursuit of Health'' (Beacon Press, 2011). <br />
<br />
It has become increasingly evident with regard to prostate cancer or breast cancer that, “While it may seem that screening can only help you, it can also hurt you: it can lead you to being overdiagnosed and treated needlessly.” Consider a different cancer, one far less frequent: thyroid cancer. According to Welch, the ratio of prostate cancer deaths to diagnoses is 1 to 6 but the ratio for thyroid cancer is 1 to 20. <br />
<br />
<blockquote>One possible explanation for this, as you will recall from similar issues with prostate cancer, is that we are really, really good at treating thyroid cancer. The other is less optimistic: that many of the diagnosed cancers didn’t need treatment in the first place. <br />
</blockquote><br />
Further, despite the “dramatic growth in the number of thyroid cancers found,” “The death rate for thyroid cancer is rock-solid stable.” He puts it boldly for thyroid cancer: “Here there is just a downside—a lot of diagnosis and no change in mortality…there is no discernible benefit.” This overtreatment results in the unnecessary removal of the thyroid gland and the need to take medication for the rest of the person’s life.<br />
<br />
On page 64 is a time series graph that shows new thyroid cancer diagnoses and thyroid cancer deaths vs. time (1975 to 2005); new diagnoses rise inexorably with time while deaths are flatlined over the 30-year period. Two pages later there is virtually the same graph but now for melanoma and again the ratio of cancer deaths to diagnoses is high enough to speculate that “there is less an epidemic of melanoma than an epidemic of diagnoses.”<br />
<br />
One reason for the general increase in overdiagnoses is the changing of the rules, the moving of the goalposts. Thresholds for diabetes, hypertension, hyperlipidemia and osteoporosis have been changed such that the disease prevalence has increased by 14%, 35%, 86% and 85%, respectively. “Whether or not” the cutoff changes were “a good thing for the individuals is a tough question. But there is no question about whether or not it was a good thing for business. These changes substantially increased the market for treatments—and the money to be made from them.” <br />
<br />
As might be expected, the experts who set the cutoffs had financial relationships with the pharmaceutical industry which stood to gain many millions of new customers. However, “To be fair, many of these experts may be true believers…but the fact that there is so much money on the table may lead them to overestimate the benefits and harms of overdiagnosis.”<br />
<br />
The [http://www.beacon.org/productdetails.cfm?PC=2174 publisher's webpage] excerpts the Introduction to the book, and provides links to numerous reviews from current newspapers.<br />
<br />
The author was interviewed on the radio show [http://www.peoplespharmacy.com/ People's Pharmacy]; the interview can be listened to [http://www.peoplespharmacy.com/2011/05/28/815-overdiagnosed/ here].<br />
<br />
'''Discussion'''<br><br />
1. A somewhat companion book for this topic is Shannon Brownlee’s ''Overtreated: Why Too Much Medicine Is Making Us Sicker and Poorer''. Although published four years before ''Overdiagnosed'', Welch makes no reference to her book.<br />
<br />
2. [http://www.healthnewsreview.org/ HeathNewsReview.org] is an excellent weekly website that deals critically with health and medical matters, especially of harms vs. benefits, relative risks vs. absolute risks.<br />
<br />
3. Why would an overdiagnosis have health insurance consequences?<br />
<br />
4. Welch often mentions the term, “incidentaloma.” Wikipedia says “In medicine, an incidentaloma is a tumor (-oma) found by coincidence (incidental) without clinical symptoms or suspicion. It is a common problem.” Why might an incidentaloma lead to overdiagnosis?<br />
<br />
5. Lawyers and fear of a malpractice suit are discussed in the book. Why might they lead to overdiagnosis and overtreatment?<br />
<br />
Submitted by Paul Alper<br />
<br />
===A related graphic===<br />
The following graphic appeared in a 2009 ''New York Times'' article, [http://www.nytimes.com/2009/10/21/health/21cancer.html?_r=1&scp=2&sq=CT%20kolata&st=cse Cancer Society, in shift, has concerns on screenings].<br />
<center><br />
http://graphics8.nytimes.com/images/2009/10/21/health/1021-biz-cancergraphic/popup.jpg<br />
</center><br />
The article quotes Dr. Otis Brawley, chief medical officer of the American Cancer Society: “We don’t want people to panic. But I’m admitting that American medicine has overpromised when it comes to screening. The advantages to screening have been exaggerated.” <br />
<br />
See also [http://www.causeweb.org/wiki/chance/index.php/Chance_News_25#Lung_cancer_screening_may_increase_your_risk_of_dying Lung cancer screening may increase your risk of dying] from Chance News 25.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Kidney cancer==<br />
A classic example of data maps is presented by Howard Wainer in <i>Picturing the Uncertain World</i>; it can be seen [http://books.google.com/books?id=SJOnBwmMqB0C&lpg=PA9&ots=coosn8Kzx2&dq=wainer%20significance%20kidney&pg=PA9#v=onepage&q&f=false here]. Many rural counties show up in the lowest decile for kidney cancer rates, which might suggest that climate or lifestyle have some benefit. But then it is seen that adjoining, similarly rural, counties turn up in the highest decile. Shown below is a map that accompanied Wainer's discussion of the example in an article entitled [http://www.americanscientist.org/issues/feature/the-most-dangerous-equation The Most Dangerous Equation] (''American Scientist'' May-June 2007<br />
Volume 95, Number 3, p. 249). <br />
<center><br />
http://www.americanscientist.org/Libraries/images/2007327141118_846.gif<br />
</center><br />
The highest decile counties are shown in red, the lowest in green. What we are seeing the effect of variation in small samples: because the rural counties have so few people, having one case vs. no cases makes the difference between the being in the top vs. the bottom decile for standardized rates of kidney cancer!<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_73&diff=13517Chance News 732011-05-29T20:14:02Z<p>PaulAlper: /* Scaling the normal curve */</p>
<hr />
<div>==Quotations==<br />
From [http://flawofaverages.com/ <i>The Flaw of Averages</i>], by Sam L. Savage, Wiley, 2009<br />
<br />
*“Our culture encodes a strong bias either to neglect or ignore variation. We tend to focus instead on measures of central tendency, and as a result we make some terrible mistakes, often with considerable practical import.” (Stephen Jay Gould, cited p. 11)<br><br />
<br />
*“Plans based on <i>average</i> assumptions are wrong on <i>average</i>.” (Savage, p. 11)<br><br />
<br />
*“Far better an approximate answer to the right question, which is often vague, than the exact answer to the wrong question, which can always be made precise.” (John W. Tukey, cited p. 38)<br><br />
<br />
*“I have found that teaching probability and statistics is easy. The hard part is getting people to learn the stuff.” (Savage, p. 49)<br><br />
<br />
*“Statisticians often describe a numerical uncertainty using the Red Words, RANDOM VARIABLE, but I will stick with ‘uncertain number.’ …. [S]top thinking of uncertainties as single numbers and begin thinking of them as shapes, or distributions. …. If you think of an uncertain number as a bar graph, you will not be seriously misled.” (Savage, p. 59''ff'')<br><br />
<br />
*“Joe Berkson, a statistician at the Mayo Clinic, developed his own criterion, which he termed the IOT Test, or Inter Ocular Trauma Test, requiring a graph that hit you between the eyes.” (Savage, p. 325)<br><br />
<br />
See [http://www.causeweb.org/wiki/chance/index.php/Chance_News_52#The_Fl Chance News 52] for a review of <i>The Flaw of Averages</i> by Laurie Snell.<br />
<br />
Submitted by Margaret Cibes<br />
----<br />
<br />
“[O]n average Bill Gates and I can afford a new Rolls and a winter home in Provence.” (Wainer, p. 36)<br><br />
<br />
<div align=right>Howard Wainer, in [http://press.princeton.edu/titles/8863.html <i>Picturing the Uncertain World</i>]<br />
Princeton University Press, 2009</div align=right><br />
<br />
Submitted by Margaret Cibes<br />
<br />
----<br />
<br />
&quot;Using a model of no greater sophistication than that employed by Benjamin Franklin (weather generally moves from west to east), I was able to predict that the area of precipitation currently over Ohio would be hitting New Jersey by tomorrow and would stay over us until the weekend. Any fool could see it. The improvement in forecasting has not been entirely due to improvements in the mathematical models of the weather. The enormous wealth of radar and satellite data summarized into a multicolored and dynamic graph can turn anyone into an expert.&quot;<br />
<br />
<div align=right> Wainer, in ''Graphic Discovery A Trout in the Milk and Other Visual Adventures'', p. 15</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
“It is Friday 13th today and though it is still only ten in the morning some awfully unlucky things have happened. I stubbed my toe; the cat caught a shrew and left it in the middle of the kitchen floor, which was unlucky for me because I almost stepped on it, and was even more unlucky for the shrew. It is a black cat too. Clear evidence that superstition works, even for small rodents. Or perhaps not. Yesterday I broke my fingernail, but it wasn’t Friday 13th then, so that wasn’t the fates being lined up against me, it was just an accident.” <br />
<div align=right>Julian Champkin, in [http://www.significancemagazine.org/details/webexclusive/1065673/Weekly-roundup---Friday-13th-and-black-cats.html “Friday 13th and black cats”], <i>Significance</i> online, May 2011</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
----<br />
"[A] Public Policy Polling survey released Thursday found that Gingrich's favorable rating with GOP voters has dropped 27 points in the last month--from 52 percent to 38 percent."<br />
<div align=right>[http://news.yahoo.com/s/yblog_theticket/20110526/ts_yblog_theticket/tiffanys-controversy-may-be-getting-worse-for-gingrich Yahoo News], 26 May 2011</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==What's in a name?==<br />
[http://www.vpr.net/npr/135830138/ Peter, Deborah popular names for CEOs]<br><br />
VPR News Morning Edition, 29 April 2011<br />
<br />
&quot;If your name is Peter or Deborah, you're more likely to be a CEO. That's what the social networking site LinkedIn found.&quot; You can listen to the rest of this Vermont Public Radio broadcast [http://www.npr.org/templates/player/mediaPlayer.html?action=1&t=1&islist=false&id=135830138&m=135830231 here].<br />
<br />
The story was featured in a variety of news outlets:<br />
<br />
*[http://www.dailymail.co.uk/news/article-1381678/Whats-Deborah-Peter-likely-CEOs.html What's in a name? Deborah and Peter more likely to become CEOs]. ''Daily Mail'', 29 April 2011<br />
*[http://www.theglobeandmail.com/life/the-hot-button/whats-in-a-baby-name-a-future-ceo-if-youve-got-the-right-syllables/article2003049/ What’s in a baby name? A future CEO if you've got the right syllables], ''Globe and Mail'' Blog, 28 April 2011<br />
*[http://www.msnbc.msn.com/id/42780266/ns/business-livescience/t/peter-deborah-are-top-ceo-names/ 'Peter' and 'Deborah' are top CEO Names], MSNBC Business, 27 April 2011<br />
*[http://www.sfgate.com/cgi-bin/blogs/techchron/detail?entry_id=88027#ixzz1MS40gstP Peter, Deborah top LinkedIn list for most popular CEO names], ''San Francisco Chronicle'', 29 April 2011<br />
<br />
<br />
'''Discussion Question'''<br><br />
A tweeted comment on [http://www.good.is/post/linkedin-culls-membership-to-find-what-names-make-a-ceo/ this site] says: <br />
&quot;Great analysis, although this can be explained mostly by the age group ...&quot; What are the implications of this? How might you explore them?<br />
<br />
Submitted by Jeanne Albert<br />
<br />
==Scaling the normal curve==<br />
[http://press.princeton.edu/titles/8863.html <i>Picturing the Uncertain World</i>]<br><br />
by Howard Wainer, Princeton, 2009, p. 171.<br><br />
<br />
This book is a collection of articles that Wainer had authored/co-authored in <i>Chance</i> (2000-2007), <i>American Scientist</i> (2007), and <i>American Statistician</i> (1996). <br />
<br />
In Chapter 16, "Galton's Normal," Wainer gives an example of the relative heights of the points on a standard normal curve and of why our sketches of normal curves do not, and cannot, come close to accurate scale drawings.<br><br />
<br />
He calculates that, even if the height at z = 13 were only 1 mm, then the height of the normal curve at the center, z = 0, would be about 5 x 10^30 km, or 5.3 x 10^17 light years. This is equivalent to a height that would be 3.4 million times larger than the universe. (His figures check out.)<br />
<br />
<blockquote>Even if the height were 1 mm at z = 6, the height at z = 0 would be 66 km. Thus it still could not be drawn to scale.</blockquote> <br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Defined by rankings==<br />
[http://www.nytimes.com/2011/04/23/your-money/23shortcuts.html?src=recg In a data-heavy society, being defined by the numbers]<br><br />
by Alina Tugend , ''New York Times'', 22 April 2011<br />
<br />
On a humorous note, the author confesses that since joining Twitter she can't help<br />
regularly checking her number of followers. But the more serious question is this:<br />
Are we as a society too dependent on numerical rankings? The article quotes MIT professor Sherry Turkle:<br />
&quot;One of the fantasies of numerical ranking is that you know how you got there. But the problem is if the <br />
numbers are arrived at in an irrational way, or black-boxed,<br />
so we don’t understand how we got there, then what use are they?<br />
&quot;<br />
<br />
The article gives several examples, two of which happen to correspond to stories that were recently discussed in Chance News 71, namely<br />
[http://www.causeweb.org/wiki/chance/index.php/Chance_News_71#Gladwell_on_college_ranks college rankings]<br />
and New York City's <br />
[http://www.causeweb.org/wiki/chance/index.php/Chance_News_71#Formulas_for_rating_teachers formula for rating teachers].<br />
<br />
Submitted by Bill Peterson<br />
<br />
==Identifying Osama bin Laden==<br />
[http://online.wsj.com/article/SB10001424052748703992704576305062901952434.html?KEYWORDS=bialik “Matching Science of DNA With Art of Identification”]<br> <br />
by Carl Bialik, <i>The Wall Street Journal</i>, May 7, 2011<br><br />
[http://blogs.wsj.com/numbersguy/dna-and-bin-ladens-positive-id-1057/tab/print/ “DNA and Bin Laden’s Positive ID”]<br><br />
by Carl Bialik, The Numbers Guy Blog, <i>The Wall Street Journal</i>, May 6, 2011<br><br />
<br />
Bialik discusses the prosecutor’s fallacy in the context of reporting about the identification of Osama bin Laden’s body. He does not dispute the identification made by government officials, said to have been based on a number of factors, including DNA. However, he reminds readers that “claimed match probabilities, such as 99% or 99.99%, can be misstated or misleading” and that further details about a DNA test, as well as evidence related to other factors, must be taken into account before having confidence in an identification.<br />
<br />
<blockquote>The problem boils down to this: A very small chance of a false positive in a genetic test isn't the same thing as a very large chance of a positive identification. </blockquote><br />
And he adds:<br />
<blockquote>One complicating factor with interpreting genetic-identity tests … is that the probability of a positive match depends on what other information is available to confirm or reject it — despite the so-called <i>prosecutor’s fallacy</i> that confuses the two. These other factors, collected in what is called “prior odds” of a positive match, can be difficult to measure. “Many factors (e.g., age, sex, appearance, clothes, etc.) are relevant to prior odds, and there are no standard rule[s] for quantify[ing] them, [according to a University of South Texas scientist].” <br />
</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
==Superstitution==<br />
[http://www.significancemagazine.org/details/webexclusive/1065673/Weekly-roundup---Friday-13th-and-black-cats.html “Friday 13th and black cats”]<br><br />
by Julian Champkin, <i>Significance</i> online, May 2011<br><br />
<br />
Champkin wrote this brief column about superstitution, probably because May 13, 2011, was a “Friday the 13th.” (See his Forsooth quotation above.) <br />
<br />
In one part of the column, he says that there are 25 finalists, on average, in the Eurovision Song Contest and goes on to suggest a winning strategy for betting:<br />
<br />
<blockquote>Did you know that if you touch your left ear with your right thumb and wiggle your toes when the country you want to win begins to sing, that country will inevitably lose? It is a superstition that I have just invented, but I bet it works. Try it tomorrow and see.</blockquote> <br />
<br />
Champkin goes on to say, “My bet will work overwhelmingly well, on average.” <br />
<br />
===Discussion===<br />
<br />
Give a statistical reason why Champkin’s method would work well, on average, with or without touching your ear and wiggling your toes. <br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Think tanks and common sense==<br />
[http://fivethirtyeight.blogs.nytimes.com/2011/05/20/thinktanks-gone-wild-on-the-economics-of-mass-transit-and-the-value-of-common-sense/#more-10393?gwh=5F22CDD4014DCD07F981DE0F9D3D78B7 On the economics of mass transit and the value of common sense]<br><br />
by Nate Silver, FiveThirtyEight blog, ''New York Times'', 20 May 2011<br />
<br />
Silver criticizes a Brookings Institution <br />
[http://www.brookings.edu/reports/2011/0512_jobs_and_transit.aspx study] of mass transit in the U.S.;<br />
he is surprised that it came to such strange numerical results:<br />
"New York, however, ranked just 13th. Washington ranked 17th. And Chicago ranked 46th — well behind Los Angeles (24th).<br />
Instead, the top 10 metro areas [for public transport] according to Brookings were Honolulu; San Jose, Calif.; Salt Lake City; Tucson; Fresno, Calif.; Denver; Albuquerque; Las Vegas; Provo, Utah; and Modesto, Calif."<br />
<br />
He concludes with:<br />
<blockquote><br />
I want to point out that just because a study uses objective criteria, that doesn’t make it sensible. In fact, studies that try to rank or rate things seem especially susceptible to slapdash, unthoughtful methodology (here is another example: a study which concludes that Gainesville, Fla., is a more gay-friendly city than San Francisco). If you come up with a result that defies common sense — like Modesto’s having better public transit than New York — then once in a blue moon, you may be on to something: conventional wisdom is fallible. But much, much more often, it’s a sign that you’ve done something wrong, and it’s time to reconsider your assumptions before publishing.<br />
</blockquote><br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_73&diff=13516Chance News 732011-05-29T20:13:15Z<p>PaulAlper: /* Think tanks and common sense */</p>
<hr />
<div>==Quotations==<br />
From [http://flawofaverages.com/ <i>The Flaw of Averages</i>], by Sam L. Savage, Wiley, 2009<br />
<br />
*“Our culture encodes a strong bias either to neglect or ignore variation. We tend to focus instead on measures of central tendency, and as a result we make some terrible mistakes, often with considerable practical import.” (Stephen Jay Gould, cited p. 11)<br><br />
<br />
*“Plans based on <i>average</i> assumptions are wrong on <i>average</i>.” (Savage, p. 11)<br><br />
<br />
*“Far better an approximate answer to the right question, which is often vague, than the exact answer to the wrong question, which can always be made precise.” (John W. Tukey, cited p. 38)<br><br />
<br />
*“I have found that teaching probability and statistics is easy. The hard part is getting people to learn the stuff.” (Savage, p. 49)<br><br />
<br />
*“Statisticians often describe a numerical uncertainty using the Red Words, RANDOM VARIABLE, but I will stick with ‘uncertain number.’ …. [S]top thinking of uncertainties as single numbers and begin thinking of them as shapes, or distributions. …. If you think of an uncertain number as a bar graph, you will not be seriously misled.” (Savage, p. 59''ff'')<br><br />
<br />
*“Joe Berkson, a statistician at the Mayo Clinic, developed his own criterion, which he termed the IOT Test, or Inter Ocular Trauma Test, requiring a graph that hit you between the eyes.” (Savage, p. 325)<br><br />
<br />
See [http://www.causeweb.org/wiki/chance/index.php/Chance_News_52#The_Fl Chance News 52] for a review of <i>The Flaw of Averages</i> by Laurie Snell.<br />
<br />
Submitted by Margaret Cibes<br />
----<br />
<br />
“[O]n average Bill Gates and I can afford a new Rolls and a winter home in Provence.” (Wainer, p. 36)<br><br />
<br />
<div align=right>Howard Wainer, in [http://press.princeton.edu/titles/8863.html <i>Picturing the Uncertain World</i>]<br />
Princeton University Press, 2009</div align=right><br />
<br />
Submitted by Margaret Cibes<br />
<br />
----<br />
<br />
&quot;Using a model of no greater sophistication than that employed by Benjamin Franklin (weather generally moves from west to east), I was able to predict that the area of precipitation currently over Ohio would be hitting New Jersey by tomorrow and would stay over us until the weekend. Any fool could see it. The improvement in forecasting has not been entirely due to improvements in the mathematical models of the weather. The enormous wealth of radar and satellite data summarized into a multicolored and dynamic graph can turn anyone into an expert.&quot;<br />
<br />
<div align=right> Wainer, in ''Graphic Discovery A Trout in the Milk and Other Visual Adventures'', p. 15</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
“It is Friday 13th today and though it is still only ten in the morning some awfully unlucky things have happened. I stubbed my toe; the cat caught a shrew and left it in the middle of the kitchen floor, which was unlucky for me because I almost stepped on it, and was even more unlucky for the shrew. It is a black cat too. Clear evidence that superstition works, even for small rodents. Or perhaps not. Yesterday I broke my fingernail, but it wasn’t Friday 13th then, so that wasn’t the fates being lined up against me, it was just an accident.” <br />
<div align=right>Julian Champkin, in [http://www.significancemagazine.org/details/webexclusive/1065673/Weekly-roundup---Friday-13th-and-black-cats.html “Friday 13th and black cats”], <i>Significance</i> online, May 2011</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
----<br />
"[A] Public Policy Polling survey released Thursday found that Gingrich's favorable rating with GOP voters has dropped 27 points in the last month--from 52 percent to 38 percent."<br />
<div align=right>[http://news.yahoo.com/s/yblog_theticket/20110526/ts_yblog_theticket/tiffanys-controversy-may-be-getting-worse-for-gingrich Yahoo News], 26 May 2011</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==What's in a name?==<br />
[http://www.vpr.net/npr/135830138/ Peter, Deborah popular names for CEOs]<br><br />
VPR News Morning Edition, 29 April 2011<br />
<br />
&quot;If your name is Peter or Deborah, you're more likely to be a CEO. That's what the social networking site LinkedIn found.&quot; You can listen to the rest of this Vermont Public Radio broadcast [http://www.npr.org/templates/player/mediaPlayer.html?action=1&t=1&islist=false&id=135830138&m=135830231 here].<br />
<br />
The story was featured in a variety of news outlets:<br />
<br />
*[http://www.dailymail.co.uk/news/article-1381678/Whats-Deborah-Peter-likely-CEOs.html What's in a name? Deborah and Peter more likely to become CEOs]. ''Daily Mail'', 29 April 2011<br />
*[http://www.theglobeandmail.com/life/the-hot-button/whats-in-a-baby-name-a-future-ceo-if-youve-got-the-right-syllables/article2003049/ What’s in a baby name? A future CEO if you've got the right syllables], ''Globe and Mail'' Blog, 28 April 2011<br />
*[http://www.msnbc.msn.com/id/42780266/ns/business-livescience/t/peter-deborah-are-top-ceo-names/ 'Peter' and 'Deborah' are top CEO Names], MSNBC Business, 27 April 2011<br />
*[http://www.sfgate.com/cgi-bin/blogs/techchron/detail?entry_id=88027#ixzz1MS40gstP Peter, Deborah top LinkedIn list for most popular CEO names], ''San Francisco Chronicle'', 29 April 2011<br />
<br />
<br />
'''Discussion Question'''<br><br />
A tweeted comment on [http://www.good.is/post/linkedin-culls-membership-to-find-what-names-make-a-ceo/ this site] says: <br />
&quot;Great analysis, although this can be explained mostly by the age group ...&quot; What are the implications of this? How might you explore them?<br />
<br />
Submitted by Jeanne Albert<br />
<br />
==Scaling the normal curve==<br />
[http://press.princeton.edu/titles/8863.html <i>Picturing the Uncertain World</i>]<br><br />
by Howard Wainer, Princeton, 2009, p. 171.<br><br />
<br />
This book is a collection of articles that Wainer had authored/co-authored in <i>Chance</i> (2000-2007), <i>American Scientist</i> (2007), and <i>American Statistician</i> (1996). <br />
<br />
In Chapter 16, "Galton's Normal," Wainter gives an example of the relative heights of the points on a standard normal curve and of why our sketches of normal curves do not, and cannot, come close to accurate scale drawings.<br><br />
<br />
He calculates that, even if the height at z = 13 were only 1 mm, then the height of the normal curve at the center, z = 0, would be about 5 x 10^30 km, or 5.3 x 10^17 light years. This is equivalent to a height that would be 3.4 million times larger than the universe. (His figures check out.)<br />
<br />
<blockquote>Even if the height were 1 mm at z = 6, the height at z = 0 would be 66 km. Thus it still could not be drawn to scale.</blockquote> <br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Defined by rankings==<br />
[http://www.nytimes.com/2011/04/23/your-money/23shortcuts.html?src=recg In a data-heavy society, being defined by the numbers]<br><br />
by Alina Tugend , ''New York Times'', 22 April 2011<br />
<br />
On a humorous note, the author confesses that since joining Twitter she can't help<br />
regularly checking her number of followers. But the more serious question is this:<br />
Are we as a society too dependent on numerical rankings? The article quotes MIT professor Sherry Turkle:<br />
&quot;One of the fantasies of numerical ranking is that you know how you got there. But the problem is if the <br />
numbers are arrived at in an irrational way, or black-boxed,<br />
so we don’t understand how we got there, then what use are they?<br />
&quot;<br />
<br />
The article gives several examples, two of which happen to correspond to stories that were recently discussed in Chance News 71, namely<br />
[http://www.causeweb.org/wiki/chance/index.php/Chance_News_71#Gladwell_on_college_ranks college rankings]<br />
and New York City's <br />
[http://www.causeweb.org/wiki/chance/index.php/Chance_News_71#Formulas_for_rating_teachers formula for rating teachers].<br />
<br />
Submitted by Bill Peterson<br />
<br />
==Identifying Osama bin Laden==<br />
[http://online.wsj.com/article/SB10001424052748703992704576305062901952434.html?KEYWORDS=bialik “Matching Science of DNA With Art of Identification”]<br> <br />
by Carl Bialik, <i>The Wall Street Journal</i>, May 7, 2011<br><br />
[http://blogs.wsj.com/numbersguy/dna-and-bin-ladens-positive-id-1057/tab/print/ “DNA and Bin Laden’s Positive ID”]<br><br />
by Carl Bialik, The Numbers Guy Blog, <i>The Wall Street Journal</i>, May 6, 2011<br><br />
<br />
Bialik discusses the prosecutor’s fallacy in the context of reporting about the identification of Osama bin Laden’s body. He does not dispute the identification made by government officials, said to have been based on a number of factors, including DNA. However, he reminds readers that “claimed match probabilities, such as 99% or 99.99%, can be misstated or misleading” and that further details about a DNA test, as well as evidence related to other factors, must be taken into account before having confidence in an identification.<br />
<br />
<blockquote>The problem boils down to this: A very small chance of a false positive in a genetic test isn't the same thing as a very large chance of a positive identification. </blockquote><br />
And he adds:<br />
<blockquote>One complicating factor with interpreting genetic-identity tests … is that the probability of a positive match depends on what other information is available to confirm or reject it — despite the so-called <i>prosecutor’s fallacy</i> that confuses the two. These other factors, collected in what is called “prior odds” of a positive match, can be difficult to measure. “Many factors (e.g., age, sex, appearance, clothes, etc.) are relevant to prior odds, and there are no standard rule[s] for quantify[ing] them, [according to a University of South Texas scientist].” <br />
</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
==Superstitution==<br />
[http://www.significancemagazine.org/details/webexclusive/1065673/Weekly-roundup---Friday-13th-and-black-cats.html “Friday 13th and black cats”]<br><br />
by Julian Champkin, <i>Significance</i> online, May 2011<br><br />
<br />
Champkin wrote this brief column about superstitution, probably because May 13, 2011, was a “Friday the 13th.” (See his Forsooth quotation above.) <br />
<br />
In one part of the column, he says that there are 25 finalists, on average, in the Eurovision Song Contest and goes on to suggest a winning strategy for betting:<br />
<br />
<blockquote>Did you know that if you touch your left ear with your right thumb and wiggle your toes when the country you want to win begins to sing, that country will inevitably lose? It is a superstition that I have just invented, but I bet it works. Try it tomorrow and see.</blockquote> <br />
<br />
Champkin goes on to say, “My bet will work overwhelmingly well, on average.” <br />
<br />
===Discussion===<br />
<br />
Give a statistical reason why Champkin’s method would work well, on average, with or without touching your ear and wiggling your toes. <br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Think tanks and common sense==<br />
[http://fivethirtyeight.blogs.nytimes.com/2011/05/20/thinktanks-gone-wild-on-the-economics-of-mass-transit-and-the-value-of-common-sense/#more-10393?gwh=5F22CDD4014DCD07F981DE0F9D3D78B7 On the economics of mass transit and the value of common sense]<br><br />
by Nate Silver, FiveThirtyEight blog, ''New York Times'', 20 May 2011<br />
<br />
Silver criticizes a Brookings Institution <br />
[http://www.brookings.edu/reports/2011/0512_jobs_and_transit.aspx study] of mass transit in the U.S.;<br />
he is surprised that it came to such strange numerical results:<br />
"New York, however, ranked just 13th. Washington ranked 17th. And Chicago ranked 46th — well behind Los Angeles (24th).<br />
Instead, the top 10 metro areas [for public transport] according to Brookings were Honolulu; San Jose, Calif.; Salt Lake City; Tucson; Fresno, Calif.; Denver; Albuquerque; Las Vegas; Provo, Utah; and Modesto, Calif."<br />
<br />
He concludes with:<br />
<blockquote><br />
I want to point out that just because a study uses objective criteria, that doesn’t make it sensible. In fact, studies that try to rank or rate things seem especially susceptible to slapdash, unthoughtful methodology (here is another example: a study which concludes that Gainesville, Fla., is a more gay-friendly city than San Francisco). If you come up with a result that defies common sense — like Modesto’s having better public transit than New York — then once in a blue moon, you may be on to something: conventional wisdom is fallible. But much, much more often, it’s a sign that you’ve done something wrong, and it’s time to reconsider your assumptions before publishing.<br />
</blockquote><br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_71&diff=11947Chance News 712011-02-18T01:29:36Z<p>PaulAlper: /* Bayesians and Bem's paper */</p>
<hr />
<div>==Quotations==<br />
&quot;Regression, it seems has a particular ability to reduce otherwise emotionally healthy adults to an infantile state, blubbing hysterically and looking for someone's hand to hold. My guess is that this suits most statisticians just fine--a textbook on regression might look like a bunch of formulas to you; to statisticians like me, it 450 pages of job security.&quot;<br />
<div align=right>Andrew Vickers, in [http://www.amazon.com/p-value-Stories-Actually-Understand-Statistics/dp/0321629302 What is a p-value anyway?]<br><br />
(Addison-Wesley, 2009), p. 78<br />
</div align=right><br />
<br />
&quot;It is an odd feeling when you love what you do and everyone else seems to hate it. I get to peer into lists of numbers and tease out knowledge that can help people live longer, healthier lives. But if I tell friends I get a kick out of statistics, they inch away as if I have a communicable disease.&quot;<br />
<div align=right>Vickers, p. ix<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
When did they start doing factoids?<br />
<blockquote>'''12%''': The percentage higher for searches of the word "guacamole" in Wisconsin than in Pennsylvania.<br><br />
'''5%''': The percentage higher for "baba ganoush" searches in Pennsylvania than in Wisconsin.<br />
</blockquote><br />
<br />
<div align=right>in &quot;The Count,&quot; ''Wall Street Journal'', 4 February 2011, p. D3<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Getting what you pay for in college==<br />
<br />
[http://www.nytimes.com/2011/02/04/education/04colleges.html Flurry of Data as Rules Near for Commercial Colleges] Tamar Lewin, The New York Times, February 4, 2011.<br />
<br />
It costs a lot of money to go to college. If you are able to get a better job as a result, that is money well invested. But that is not always the case, and it may be that commercial colleges have more problems with this.<br />
<br />
<blockquote>On Thursday, the department issued new data showing that many commercial colleges leave large numbers of their graduates unable to pay back their loans. The data — covering all institutions of higher education — found that among students whose loans came due in 2008, 25 percent of those who attended commercial colleges defaulted within three years, compared with 10.8 percent at public institutions and 7.6 percent at private nonprofit colleges and universities. </blockquote><br />
<br />
That's not a fair comparison, according to some.<br />
<br />
<blockquote>"Our schools are primarily educating working adults and lower income students, which is not true of traditional higher education," said Harris Miller, president of the Association of Private Sector Colleges and Universities. "My expectation is that if you compared schools with our demographics, they would have similar rates, and I don’t understand why the Department of Education can’t break it down that way."</blockquote><br />
<br />
There will soon be penalties for colleges with poor data on loan repayment performance.<br />
<br />
<blockquote>Starting next year, colleges that have default rates greater than 30 percent for three consecutive years will, as of 2014, lose their eligibility for federal student aid.</blockquote><br />
<br />
There are differing opinions on whether this is a good thing.<br />
<br />
<blockquote>The commercial colleges say the rule, as proposed, would cut off education opportunities for low-income and minority students with too few educational options. But consumer advocacy groups say that it would eliminate only the programs whose students have the highest loan-default rates, and, in the process, help protect both students and taxpayers from programs that take in millions of dollars of federal aid but leave students mired in debt.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Should loan default rates be adjusted for the demographics of the student population?<br />
<br />
2. What sort of data, other than loan default rates could be collected to measure how effective colleges are.<br />
<br />
==Bayesians and Bem's paper==<br />
<br />
Bayesian statisticians have many criticisms of [http://www.causeweb.org/wiki/chance/index.php/Chance_News_70#New_ESP_study_raises_ruckus Bem’s paper.] Perhaps the major one is Bem’s reliance on low p-value to show that ESP exists. In the Bayesian world, unlike the frequentist one, p-value is viewed as a flawed metric for testing hypotheses. The following is a hypothetical example from [http://onlinelibrary.wiley.com/doi/10.1002/sim.4780121510/abstract Freeman]:<br />
<center><br />
{| border="1" style="text-align:center" cellpadding="3"<br />
| Number of Patients<br>Receiving A and B || Numbers <br>Preferring A:B || % <br>Preferring A || two-sided <br>p-value<br />
|-<br />
| 20 || 15: 5 || 75.00 || 0.04 <br />
|-<br />
| 200 || 115: 86 || 57.50 || 0.04<br />
|-<br />
| 2000 || 1046: 954 || 52.30 || 0.04<br />
|-<br />
| 2000000 || 1001445: 998555 || 50.07 || 0.04 <br />
|} <br />
</center><br />
The p-value is numerically the same regardless of sample size; in particular, the last row is evidence that treatment A and B are equivalent despite the continuing low p-value. To bring things back to Bem’s paper, assume that treatment A has ESP and B does not.<br />
<br />
Here is another [http://en.wikipedia.org/wiki/Lindley%27s_paradox example known as Lindley’s paradox] which demonstrates that p-value is a flawed metric; such analysis was first published about 80 years ago. Although this example involves 98,451 births of boys and girls, it could just as well deal with ESP successes and failures.<br />
<blockquote><br />
Let's imagine a certain town where 49,581 boys and 48,870 girls have been born over a certain time period. The observed proportion (''x'') of male births is thus 49,581/98,451 = 0.5036. We are interested in testing whether the true proportion (''&theta;'') is 0.5. That is, our null hypothesis is <br />
&nbsp;H<sub>0</sub>: ''&theta;'' = 0.5&nbsp; and the alternative is &nbsp;H<sub>1</sub>: ''&theta;'' &ne; 0.5.<br />
</blockquote><br />
Because the sample size is very large, the normal approximation to the binomial holds; the mean proportion under the null is .5 and the variance is &nbsp;''&sigma;''<sup>2</sup> &asymp; ''x''(1&minus;''x'')/''n'', or (.5036)(.4964)/98,451. <br />
<br />
Using the normal approximation above, the upper tail probability is the one-sided p-value<br />
<center><br />
http://community.middlebury.edu/~wpeterso/Chance_News/images/CN71_Bem1.png<br />
</center><br />
By symmetry, the two-sided p-value is double that, .0234 which indicates statistical significance. <br />
<br />
However, if we assume we have no reason to believe that the proportion of male births should be different from 0.5, so we assign prior probabilities ''P''(''&theta;'' = 0.5) = 0.5 and ''P''(''&theta;'' &ne; 0.5) = 0.5, the latter uniformly distributed between 0 and 1. The prior distribution is thus a mixture of point mass 0.5 and a uniform distribution ''U''(0,1) . This leads to <br />
<br />
<center><br />
http://community.middlebury.edu/~wpeterso/Chance_News/images/CN71_Bem2.png<br />
</center><br />
This is strong evidence in favor of &nbsp;H<sub>0</sub>: ''&theta;'' = 0.5. Consequently, despite the low p-value, we have a high probability the null is correct.<br />
<br />
If p-value is so flawed, the natural question is: why is it so ubiquitous? One answer is that it is a mathematical procedure which is much easier to perform; indeed, before the availability of stats packages, students ignorant of calculus could readily use the standard normal table to carry out the frequentist calculation. Further, the pesky (but fundamentally important to Bayesians) issue of prior probabilities is sidestepped entirely. For decades the Bayesian triumph has been predicted but thus far, the U.S. remains a frequentist stronghold and p-values galore are published.<br />
<br />
But there is another issue regarding Bem’s paper which is outside of the domain of statistics. Why do so many people passionately believe in ESP even though there has never been any credible evidence for it outside of a low p-value? Perhaps the answer lies in a weird perversion of the notion of democratic opinion. If ESP exists then physical laws, the specialty of the scientifically and mathematically educated, no longer hold and everyone has an equal say. Beauty may lie in the eyes of the beholder, but it is incontestable that the speed of light is approximately 299,792,458 meters per second, the harmonic series diverges and the planet on which we reside is considerably older than a few thousand years. Such items are not up for a vote and should not be subject to the ballot box of public estimation.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_71&diff=11942Chance News 712011-02-18T01:05:27Z<p>PaulAlper: /* Bayesians and Bem's paper */</p>
<hr />
<div>==Quotations==<br />
&quot;Regression, it seems has a particular ability to reduce otherwise emotionally healthy adults to an infantile state, blubbing hysterically and looking for someone's hand to hold. My guess is that this suits most statisticians just fine--a textbook on regression might look like a bunch of formulas to you; to statisticians like me, it 450 pages of job security.&quot;<br />
<div align=right>Andrew Vickers, in [http://www.amazon.com/p-value-Stories-Actually-Understand-Statistics/dp/0321629302 What is a p-value anyway?]<br><br />
(Addison-Wesley, 2009), p. 78<br />
</div align=right><br />
<br />
&quot;It is an odd feeling when you love what you do and everyone else seems to hate it. I get to peer into lists of numbers and tease out knowledge that can help people live longer, healthier lives. But if I tell friends I get a kick out of statistics, they inch away as if I have a communicable disease.&quot;<br />
<div align=right>Vickers, p. ix<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
When did they start doing factoids?<br />
<blockquote>'''12%''': The percentage higher for searches of the word "guacamole" in Wisconsin than in Pennsylvania.<br><br />
'''5%''': The percentage higher for "baba ganoush" searches in Pennsylvania than in Wisconsin.<br />
</blockquote><br />
<br />
<div align=right>in &quot;The Count,&quot; ''Wall Street Journal'', 4 February 2011, p. D3<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Getting what you pay for in college==<br />
<br />
[http://www.nytimes.com/2011/02/04/education/04colleges.html Flurry of Data as Rules Near for Commercial Colleges] Tamar Lewin, The New York Times, February 4, 2011.<br />
<br />
It costs a lot of money to go to college. If you are able to get a better job as a result, that is money well invested. But that is not always the case, and it may be that commercial colleges have more problems with this.<br />
<br />
<blockquote>On Thursday, the department issued new data showing that many commercial colleges leave large numbers of their graduates unable to pay back their loans. The data — covering all institutions of higher education — found that among students whose loans came due in 2008, 25 percent of those who attended commercial colleges defaulted within three years, compared with 10.8 percent at public institutions and 7.6 percent at private nonprofit colleges and universities. </blockquote><br />
<br />
That's not a fair comparison, according to some.<br />
<br />
<blockquote>"Our schools are primarily educating working adults and lower income students, which is not true of traditional higher education," said Harris Miller, president of the Association of Private Sector Colleges and Universities. "My expectation is that if you compared schools with our demographics, they would have similar rates, and I don’t understand why the Department of Education can’t break it down that way."</blockquote><br />
<br />
There will soon be penalties for colleges with poor data on loan repayment performance.<br />
<br />
<blockquote>Starting next year, colleges that have default rates greater than 30 percent for three consecutive years will, as of 2014, lose their eligibility for federal student aid.</blockquote><br />
<br />
There are differing opinions on whether this is a good thing.<br />
<br />
<blockquote>The commercial colleges say the rule, as proposed, would cut off education opportunities for low-income and minority students with too few educational options. But consumer advocacy groups say that it would eliminate only the programs whose students have the highest loan-default rates, and, in the process, help protect both students and taxpayers from programs that take in millions of dollars of federal aid but leave students mired in debt.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Should loan default rates be adjusted for the demographics of the student population?<br />
<br />
2. What sort of data, other than loan default rates could be collected to measure how effective colleges are.<br />
<br />
==Bayesians and Bem's paper==<br />
<br />
Bayesian statisticians have many criticisms of Bem’s paper. Perhaps the major one is Bem’s reliance on low p-value to show that ESP exists. In the Bayesian world, unlike the frequentist one, p-value is viewed as a flawed metric for testing hypotheses. The following is a hypothetical example from [http://onlinelibrary.wiley.com/doi/10.1002/sim.4780121510/abstract Freeman]:<br />
<center><br />
{| border="1" style="text-align:center" cellpadding="3"<br />
| Number of Patients<br>Receiving A and B || Numbers <br>Preferring A:B || % <br>Preferring A || two-sided <br>p-value<br />
|-<br />
| 20 || 15: 5 || 75.00 || 0.04 <br />
|-<br />
| 200 || 115: 86 || 57.50 || 0.04<br />
|-<br />
| 2000 || 1046: 954 || 52.30 || 0.04<br />
|-<br />
| 2000000 || 1001445: 998555 || 50.07 || 0.04 <br />
|} <br />
</center><br />
The p-value is numerically the same regardless of sample size; in particular, the last row is evidence that treatment A and B are equivalent despite the continuing low p-value. To bring things back to Bem’s paper, assume that treatment A has ESP and B does not.<br />
<br />
Here is another [http://en.wikipedia.org/wiki/Lindley%27s_paradox example known as Lindley’s paradox] which demonstrates that p-value is a flawed metric; such analysis was first published about 80 years ago. Although this example involves 98,451 births of boys and girls, it could just as well deal with ESP successes and failures.<br />
<blockquote><br />
Let's imagine a certain town where 49,581 boys and 48,870 girls have been born over a certain time period. The observed proportion (''x'') of male births is thus 49,581/98,451 = 0.5036. We are interested in testing whether the true proportion (''&theta;'') is 0.5. That is, our null hypothesis is <br />
&nbsp;H<sub>0</sub>: ''&theta;'' = 0.5&nbsp; and the alternative is &nbsp;H<sub>1</sub>: ''&theta;'' &ne; 0.5.<br />
</blockquote><br />
Because the sample size is very large, the normal approximation to the binomial holds; the mean proportion under the null is .5 and the variance is &nbsp;''&sigma;''<sup>2</sup> &asymp; ''x''(1&minus;''x'')/''n'', or (.5036)(.4964)/98,451. <br />
<br />
Using the normal approximation above, the upper tail probability is the one-sided p-value<br />
<center><br />
http://community.middlebury.edu/~wpeterso/Chance_News/images/CN71_Bem1.png<br />
</center><br />
By symmetry, the two-sided p-value is double that, .0234 which indicates statistical significance. <br />
<br />
However, if we assume we have no reason to believe that the proportion of male births should be different from 0.5, so we assign prior probabilities ''P''(''&theta;'' = 0.5) = 0.5 and ''P''(''&theta;'' &ne; 0.5) = 0.5, the latter uniformly distributed between 0 and 1. The prior distribution is thus a mixture of point mass 0.5 and a uniform distribution ''U''(0,1) . This leads to <br />
<br />
<center><br />
http://community.middlebury.edu/~wpeterso/Chance_News/images/CN71_Bem2.png<br />
</center><br />
This is strong evidence in favor of &nbsp;H<sub>0</sub>: ''&theta;'' = 0.5. Consequently, despite the low p-value, we have a high probability the null is correct.<br />
<br />
If p-value is so flawed, the natural question is: why is it so ubiquitous? One answer is that it is a mathematical procedure which is much easier to perform; indeed, before the availability of stats packages, students ignorant of calculus could readily use the standard normal table to carry out the frequentist calculation. Further, the pesky (but fundamentally important to Bayesians) issue of prior probabilities is sidestepped entirely. For decades the Bayesian triumph has been predicted but thus far, the U.S. remains a frequentist stronghold and p-values galore are published.<br />
<br />
But there is another issue regarding Bem’s paper which is outside of the domain of statistics. Why do so many people passionately believe in ESP even though there has never been any credible evidence for it outside of a low p-value? Perhaps the answer lies in a weird perversion of the notion of democratic opinion. If ESP exists then physical laws, the specialty of the scientifically and mathematically educated, no longer hold and everyone has an equal say. Beauty may lie in the eyes of the beholder, but it is incontestable that the speed of light is approximately 299,792,458 meters per second, the harmonic series diverges and the planet on which we reside is considerably older than a few thousand years. Such items are not up for a vote and should not be subject to the ballot box of public estimation.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_70&diff=11755Chance News 702011-01-10T21:03:47Z<p>PaulAlper: /* Go figure, go finger */</p>
<hr />
<div>==Quotations==<br />
&quot;The interpretation of statistical signiﬁcance tests is liable to a misconception known <br />
as the fallacy of the transposed conditional. In this fallacy, the probability of the data <br />
given a hypothesis (e.g., P(D|H), such as the probability of someone being dead given that <br />
they were lynched, a probability that is close to 1) is confused with the probability of the <br />
hypothesis given the data (e.g., P(H|D), such as the probability that someone was lynched <br />
given that they are dead, a probability that is close to zero).&quot;<br />
<div align=right>Eric–Jan Wagenmakers, et.al., writing in <br><br />
[http://www.ruudwetzels.com/articles/Wagenmakersetal_subm.pdf Why psychologists must change the way they analyze their data: The case of Psi]<br></div align=right><br />
<br />
The authors are criticizing naive use of p-value in the recent ESP research controversy.<br />
<br />
Submitted by Paul Alper<br />
<br />
-----<br />
”If you averaged the highs and lows of a rollercoaster, it wouldn’t be much of a thrill ride; same with the threat of flu.”<br><br />
<div align=right>Rebecca Goldin in [http://stats.org/stories/2010/flu_variance_sept3_10.html “The flu: It’s about variance”]<br><br />
<i>STATS</i>, September 3, 2010</div align=right><br />
The author reports that CDC flu-death counts have ranged from 3,300 to almost 50,000 in various years, making the yearly average unreliable as an exclusive basis of public health decisions.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Forsooth==<br />
From a novel, <i>The Kills</i>, by Linda Fairstein, Scribner, 2004:<br />
<br />
<blockquote>“Hey, how many people do you need to have in a room to guarantee the chance that at least two of them would have the same birthday?”<br><br />
<br />
“I don’t know. Three hundred sixty-four.”<br><br />
<br />
“Hah! Twenty-three. At least two out of every twenty-three people will have exactly the same birthday. Statistical odds. A lot of life is coincidence.”</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==New ESP study raises ruckus==<br />
Read about a new study in which a Cornell psychologist claims to have verified "ESP":<br><br />
[http://abcnews.go.com/Technology/extrasensory-perception-scientific-journal-esp-paper-published-cornell/story?id=12556754 “ESP Study Gets Published in Scientific Journal], by Ned Potter, <i>ABC World News</i>, January 6, 2011 (including 2-min video interview).<br><br />
[http://www.nytimes.com/2011/01/06/science/06esp.html?_r=1&ref=benedictcarey “Journal’s paper on ESP Expected to Prompt Outrage”], by Benedict Carey, <i>The New York Times</i>, January 5, 2011.<br><br />
<br />
Read the study:<br><br />
[http://dbem.ws/FeelingFuture.pdf “Feeling the Future: Experimental Evidence for Anomalous Retroactive Influences on Cognition and Affect”], by Daryl J. Bem, Cornell University, <i>Journal of Personality and Social Psychology</i>, 2010.<br><br />
<br />
Read a rebuttal:<br><br />
[http://dl.dropbox.com/u/1018886/Bem6.pdf “Why Psychologists Must Change the Way They Analyze Their Data”], by Eric-Jan Wagenmakers <i>et al</i>., University of Amsterdam.<br><br />
<blockquote>We reanalyze Bem’s data using a default Bayesian t-test and show that the evidence for psi ["ESP"] is weak to nonexistent. …. We conclude that Bem’s p-values do not indicate evidence in favor of precognition; instead, they indicate that experimental psychologists need to change the way they conduct their experiments and analyze their data.</blockquote><br />
<br />
Submitted by Margaret Cibes based on an ISOSTAT posting by Randall Pruim<br />
<br />
===Additional discussion===<br />
For more discussion, see Andrew Gelman's blog post (1/6/11) [http://www.stat.columbia.edu/~cook/movabletype/archives/2011/01/that_silly_esp.html That silly ESP paper and some silliness in a rebuttal as well], and reader comments there.<br />
<br />
==Placebos without deception==<br />
[http://www.boston.com/lifestyle/health/articles/2010/12/23/patients_in_study_who_knew_they_were_taking_placebo_still_felt_better/?p1=Well_Health_links Patients in study who knew they were taking placebo still felt better]<br><br />
by Deborah Kotz, ''Boston Globe'', 23 December 2010<br />
<br />
Although somewhat of an exaggeration, before the invention of aspirin, MDs had nothing to offer except placebos. Today, no study in the medical field can be taken seriously without a control for the so-called placebo effect. In an unusual twist whereby the placebo is the treatment, [http://www.plosone.org/article/info:doi/10.1371/journal.pone.0015591 Kaptchuk, et al] openly beforehand informed 37 patients suffering from irritable bowl syndrome (IBS) that they were receiving a placebo “without any medication in it.” The other 43 patients were a control, i.e., no treatment, in that they received no medication whatsoever.<br />
<br />
The ''Globe'' article put it this way:<br />
<blockquote><br />
The researchers got some astounding results when they gave placebos — gelatin capsules filled with nondigestible cellulose — to patients suffering from irritable bowel syndrome for three weeks. Nearly 60 percent reported an improvement in their symptoms compared with 35 percent of the patients who took nothing beyond their usual treatments.<br />
But here is the kicker: The placebo takers knew they were popping the equivalent of sugar pills, yet they still said they experienced less abdominal pain, constipation, or loose stools during the study.<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. Here is the <br />
[http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0015591.t002&representation=PNG_M table] of treatment outcomes from the Kaptchuk paper and an associated [http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0015591.g002&representation=PNG_M graphic] (the phrase “Open Placebo” means no deception). Use a statistics package to verify the p-values given there.<br />
<br />
2. Just to confuse things now that the power of the placebo has been firmly established for IBS, consider [http://rdmag.com/News/FeedsAP/2011/01/life-sciences-antibiotic-that-targets-gut-bacteria-may-help-some/ this] which also was recently published:<br />
<blockquote><br />
In two studies involving more than 1,200 subjects with diarrhea-predominant IBS, researchers found that a two-week course of the antibiotic rifaximin helped relieve symptoms not only during treatment, but also for weeks after the medication was stopped.<br />
</blockquote><br />
<blockquote><br />
Participants who were randomly assigned to receive the drug reported less bloating and abdominal pain, and improved stool consistency for up to 10 weeks, say the authors, whose paper is published in this week's New England Journal of Medicine.<br />
</blockquote><br />
<blockquote><br />
About 40 per cent or more of subjects given the thrice-daily rifaximin pill had significantly diminished IBS symptoms compared to those given placebo, or dummy pills, the study found.<br />
</blockquote><br />
Dr. Lawrence Cohen who was not involved with the study<br />
<blockquote><br />
said rifaximin could have potential, although how much is difficult to determine because the difference in the proportion of those reporting symptom relief in the study's treated group versus the placebo group wasn't that dramatic.<br />
</blockquote><br />
<blockquote><br />
"It's statistically significant, yes. But is it clinically significant?"<br />
</blockquote><br />
<blockquote><br />
While the findings shouldn't be dismissed, Cohen said he is cautious about the study because it was designed and funded by rifaximin's maker, Salix Pharmaceuticals Inc., a fact disclosed by the researchers. Pimentel [director of the Gastrointestinal Motility Program at Cedars-Sinai Medical Center] discovered the use of rifaximin for IBS, and Cedars-Sinai holds patent rights to this discovery and has licensed those rights to Salix.<br />
</blockquote><br />
<br />
Submitted by Paul Alper<br />
<br />
==Go figure, go finger==<br />
[http://www.guardian.co.uk/science/2010/dec/01/what-finger-length-says-about-you What your fingers say about you]<br><br />
by Tim Dowling, ''Guardian'', 1 December 2010<br />
<br />
Times are hard and academics need to publish in an environment in which not a great deal of money is available for gathering data. A popular way to do things inexpensively and create a stir in the lay press is to look at finger lengths. Previous Chance News wikis on the subject of finger lengths may be found [http://www.causeweb.org/wiki/chance/index.php/Chance_News_44#2D:4D here] and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_43#Nature_vs_Nurture_and_Sexuality here]. <br />
<br />
In the present article, Tim Dowling comments on the more unusual past claims put forward in academic journals regarding finger length as destiny:<br />
<br />
<blockquote><br />
Did you know the length of your ring finger could indicate whether or not you are fertile, prone to prostate cancer or, if you are a women, likely to be a lesbian?<br />
</blockquote><blockquote><br />
…men with longer ring fingers tended to be more fertile. It's the other way round for women.<br />
</blockquote><blockquote><br />
…[financial] traders with longer ring fingers made more money than their short ring-fingered colleagues. They're also thought to be more aggressive, and more likely to take risks.<br />
</blockquote><blockquote><br />
…lesbian women tended to have the more masculine (long ring, short index) finger arrangement.<br />
</blockquote><blockquote><br />
…women with longer ring fingers did better [on spatial skills such as driving] than those whose ring fingers were equal to, or shorter than, their index fingers.<br />
</blockquote><br />
<br />
He sums up the previous results with this picture:<br />
<br><br />
<center><br />
http://static.guim.co.uk/sys-images/Guardian/About/General/2010/12/1/1291219819190/The-difference-between-yo-006.jpg<br />
</center><br />
<br><br />
However, [http://www.nature.com/bjc/journal/v104/n1/full/6605986a.html the latest connection with fingers] seems to indicate that men whose ring fingers are longer than their index fingers are more likely to develop prostate cancer. Its conclusion is “Pattern of finger lengths may be a simple marker of prostate cancer risk, with length of 2D greater than 4D suggestive of lower risk.” However, from [http://prostatecancerinfolink.net/2010/12/02/check-your-finger-lengths-if-you-want-to-but/ prostatecancerinfolink.net] we learn that<br />
<blockquote>the report in the ''British Journal of Cancer'' (2011) '''104''', 175–177. doi:10.1038/sj.bjc.6605986 is so hedged about with “mays” and “maybes” that it is unlikely to be considered definitive by too many people. We quote as follows (with bold italic type added for emphasis):<br />
</blockquote><blockquote><br />
“The ratio of digit lengths is fixed ''in utero'', and '''''may be''''' a proxy indicator for prenatal testosterone levels.”<br />
</blockquote><blockquote><br />
“Compared with index finger shorter than ring finger …, men with index finger longer than ring finger … showed a negative association, '''''suggesting''''' a protective effect with a 33% risk reduction.”<br />
</blockquote><blockquote><br />
“Pattern of finger lengths '''''may be''''' a simple marker of prostate cancer risk.”<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. [http://ecodevoevo.blogspot.com/2010/12/loving-hands-or-go-finger.html The Mermaid’s Tale] points out a possible useful aspect of this study:<br />
<blockquote><br />
Of course, on the positive side, a glance at the hand is less embarrassing than a real DRE (digital rectal exam), or a PSA [prostate specific antigen] test to look for prostate cancer. It may be as useful, at least in terms of risk. It's a lot cheaper. Of course the PSA testing companies are likely to resist this current interpretation.<br />
</blockquote><br />
<br />
Determine the typical cost of a PSA test. The PSA test is a very common screening test in the United States and much less employed in other countries such as England. What does the following graph<br />
<br><br />
<center><br />
http://jjco.oxfordjournals.org/content/35/11/690/F1.medium.gif<br />
</center><br />
<br><br />
suggest about the efficacy of screening? Although the five-year survival rates are not shown, what does the graph suggest about five-year survival rates in the various countries? What does it suggest about finger length?<br />
<br />
2. The three-page ''British Journal of Cancer'' study relating prostate cancer and finger length cites 19 authors plus two institutions, The UK Genetic Prostate Cancer Study Collaborators and British Association of Urological Surgeons' Section of Oncology, whose “Lists [are] available on request.” There were 1524 subjects who had prostate cancer and 3044 subjects in the control arm. Information is given for the right hand only.<br />
<br />
<center><br />
'''Table 2.''' Right-hand pattern and prostate cancer risk<br />
{| border="1" style="text-align:center" cellpadding="3"<br />
! Finger pattern !! Advanced cases (%)!! Controls (%) !! OR &#8224;!! 95% CI !! P-value<br />
|-<br />
|Index shorter than ring || 872 (57.2) ||1570 (51.6) ||1.00 || || <br />
|-<br />
|Index equal to ring ||305 (20.0) ||538 (17.7) ||1.05 ||0.88–1.25 || 0.580 <br />
|-<br />
|Index longer than ring ||347 (22.8) ||936 (30.8) ||0.67 ||0.57–0.80 ||<0.001<br />
|-<br />
|Total ||1524 (100.0) ||3044 (100.0) || || || <br />
|}<br />
Abbreviations: CI=confidence interval; OR=odds ratio.<br><br />
&#8224; Adjusted for age and social class.<br />
</center><br />
<br />
Unlike previous studies of finger length, finger length in this study was self-reported. Why might this be an issue?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_69&diff=11639Chance News 692010-12-24T14:47:34Z<p>PaulAlper: /* Placebo contents */</p>
<hr />
<div>==Quotations==<br />
"The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true."<br />
<div align=right>John P.A. Ioannidis,<br />
in [http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.0020124 Why most published research findings are false]<br></div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
-----<br />
<br />
"We’re not going to stop using algorithms. They’re too useful. But we need to be more aware of the algorithmic perversity that’s creeping into our lives. The short-term fit of a dating match or a Web page doesn’t measure the long-term value it may hold. <i>Statistically likely</i> does not mean correct, or just, or fair. .... It’s when people deviate from what we predict they’ll do that they prove they are individuals, set apart from all others of the human type."<br><br />
<br />
<div align=right>Alexis Madrigal, in [http://www.theatlantic.com/magazine/archive/2010/12/take-the-data-out-of-dating/8299/ "Take the Data Out of Dating"]<br><br />
<i>The Atlantic</i>, December 2010</div align=right><br />
<br />
“Several said the government is making a crucial mistake by rating performance [of dialysis clinics] by lab tests, not outcomes or measures that reflect patients’ quality of life. ‘Mortality, morbidity, and infection—that’s the bottom line,’ said [a former dialysis-clinic owner]. ‘It’s easy to adjust the labs. What good is it if you have good numbers, but everyone’s dying or in the hospital?’”<br />
<div align=right>Robin Fields, in [http://www.theatlantic.com/magazine/archive/2010/12/-8220-god-help-you-you-39-re-on-dialysis-8221/8308/ “God Help You. You’re on Dialysis.”]<br><br />
<i>The Atlantic</i>, December 2010</div align=right><br />
<br />
“I had realized from experience that university people sometimes don't react well to common sense, and in any case, most of them listen to it harder if you first intimidate them with equations."<br><br />
<div align=right>W. D. Hamilton<br><br />
quoted in a conversation with Dutch journalist FransRoes[http://www.stephenjaygould.org/library/hamilton_interview.html]</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
"If you think you already know which theory is right, you are either a major scientist who has been concealing a vast mountain of unpublished research from the rest of the world, or else you are confusing wishful thinking with knowledge."<br />
<br />
<div align=right>Daniel C. Dennett, in <br />
[http://en.wikipedia.org/wiki/Breaking_the_Spell:_Religion_as_a_Natural_Phenomenon Breaking the Spell: Religion as a Natural Phenomenon]<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
-----<br />
&quot;Instead of rhetoric, the politician favors figures of another kind: Today's infatuation with statistics is a bid for scientific exactness but tends to crowd out finesse.&quot;<br />
<br />
<div align=right>Henry Hitchings, reviewing ''Farnsworth's Classical English Rhetoric''<br><br />
in [http://online.wsj.com/article/SB10001424052748703766704576009540219126236.html?mod=googlenews_wsj: The syntax of style],<br />
Wall Street Journal, 15 December 2010<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
“The mechanics of the ghostwriter’s job are fairly simple, [an anonymous ghostwriter] says. Early on, a medical-communications agency and its pharmaceutical-company sponsors will agree on a title for an article and a potential author, usually an academic physician with a reputation as a ‘thought leader.’ The agency will ask the thought leader to ’author’ the article, sometimes in exchange for a fee. The ghostwriter will write the article, or perhaps an extended outline containing the message the company wants to transmit, and send it along to the physician, who may make some changes or simply sign it as written and submit it to a journal, usually scrubbed of any mention of the ghostwriter, the agency, or the pharmaceutical company. [The ghostwriter] says he rarely even sees the published articles he writes.” <br />
<div align=right>Carl Elliott, in [http://www.theatlantic.com/magazine/archive/2010/12/playing-doctor/8296/ “Playing Doctor”]<br><br />
<i>The Atlantic</i>, December 2010</div align=right><br />
See also [http://www.nytimes.com/2010/11/30/business/30drug.html?_r=2&partner=yahoofinance “Drug Maker Wrote Book Under 2 Doctors’ names, Documents Say”], <i>The New York Times</i>, November 29, 2010.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
"[A] former Colorado Springs state senator ... once claimed, 'I don’t know whether we need a bill on teen pregnancy because statistics show teen pregnancy drops off significantly after age 25.'”<br><br />
<br />
<div align=right>Cited in [http://coloradoindependent.com/18884/for-lawmakers-chuck-hennings-quotes-live-on-people-who-live-in-glass-houses-shouldn%E2%80%99t-bowl "For Colorado lawmakers: People who live in glass houses shouldn't bowl"]<br><br />
<i>The Colorado Independent</i>, January 7, 2009</div align=right><br />
<br />
Submitted by Margaret Cibes at the suggestion of James Greenwood<br />
<br />
-----<br />
Relationships cited in [http://www.theatlantic.com/business/archive/2009/04/department-of-awful-statistics/7182/ "Department of Awful Statistics"], <i>The Atlantic</i>, April 2, 2009<br><br />
<br />
<div align=center>http://i284.photobucket.com/albums/ll33/Jaguar_Fan_1/Lemongraph.jpg<br />
[http://s284.photobucket.com/albums/ll33/Jaguar_Fan_1/?action=view&current=Lemongraph.jpg&sort=ascending#!oZZ62QQcurrentZZhttp%3A%2F%2Fs284.photobucket.com%2Falbums%2Fll33%2FJaguar_Fan_1%2F%3Faction%3Dview%26current%3DLemongraph.jpg "photobucket"]</div align=center><br />
<br />
<div align=center>http://www.venganza.org/images/PiratesVsTemp.png<br />
[http://www.venganza.org/about/open-letter/ "Church of the Flying Spaghetti Bucket"]</div align=center><br />
<br />
Submitted by Margaret Cibes<br />
<br />
----<br />
Spurious precision?<br />
<blockquote><br />
&quot;Everybody trips on stairs at some time or other. It has been calculated that you are likely to miss a step once every 2,222 occasions you use stairs, suffer a minor accident once in every 63,000 uses, suffer a painful accident once in every 734,000, and need hospital attention once every 3,616,667 uses.&quot;<br />
</blockquote><br />
<br />
<div align=right>Bill Bryson, in ''At Home: A Short History of Private Life'', p. 309 (data from <br><br />
''The Staircase: Studies of Hazards, Falls and Safer Designs'' by John A. Templer)<br />
</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooths from the RRS News==<br />
The following Forsooths are from the December 2010 issue of the RRS News<br><br />
<br />
SLIPPER OVER:You always knew they<br><br />
were a rubbish present-now here's some<br> <br />
evidence that you really shouldn't buy<br><br />
slippers for grandma. In a US study, 52 per<br><br />
cent of elderly people who fell at home<br><br />
were barefoot or wearing slippers at the<br><br />
time. 'Therefore, older people should<br><br />
wear shoes at home whenever possible to<br><br />
minimize their risk of falling,'said study<br><br />
author Dr Marian Hannan.<br><br />
<br />
<div align=right> Metro<br><br />
24 June 2010<br><br />
</div><br />
<br />
----<br />
Temperatures will be near average, at <br>best.<br />
<br />
<div align=right>BBC Radio weather forecast<br><br />
28 August 2010<br><br />
</div><blockquote><br />
<br />
Submitted by Laurie Snell<br><br />
</blockquote><br />
<br />
==Placebo contents==<br />
<br />
According to [http://en.wikipedia.org/wiki/Placebo Wikipedia], <br />
<blockquote><br />
A placebo (''Latin: I shall please'') is a sham or simulated medical intervention that can produce a (perceived or actual) improvement, called a placebo effect.<br />
<br />
[The origin for the term placebo] dates back to a Latin translation of the Bible by Jerome. It was first used in a medicinal context in the 18th century. In 1785 it was defined as a "commonplace method or medicine" and in 1811 it was defined as "any medicine adapted more to please than to benefit the patient," sometimes with a derogatory implication. <br />
</blockquote><br />
<br />
Nowadays, so entrenched is the necessity of a comparison to a placebo, any medical treatment trial without a control arm containing a placebo would be viewed skeptically both statistically and medicinally. But, consider the provocative title of [http://www.annals.org/content/153/8/532.abstract Golomb]: “What's in Placebos: Who Knows? Analysis of Randomized, Controlled Trials.” Surprisingly,<br />
<blockquote><br />
No regulations govern placebo composition. The composition of placebos can influence trial outcomes and merits reporting.<br />
</blockquote><br />
<br />
The study looked at four prestigious journals: ''New England Journal of Medicine'', ''JAMA'', ''The Lancet'' and ''Annals of Internal Medicine''. Included were 176 journal articles:<br />
<blockquote><br />
<br />
Most studies did not disclose the composition of the study placebo. Disclosure was less common for pills than for injections and other treatments (8.2% vs. 26.7%; P = 0.002).<br />
</blockquote><br />
<blockquote><br />
'''Conclusion''': Placebos were seldom described in randomized, controlled trials of pills or capsules. Because the nature of the placebo can influence trial outcomes, placebo formulation should be disclosed in reports of placebo-controlled trials.<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. Golomb cites the following example: “For instance, olive oil and corn oil have been used as the placebo in trials of cholesterol-lowering drugs.” Under the assumption that these oils might be beneficial, rather than inert, why does this understate the positive benefit of the treatment?<br />
<br />
2. Golomb cites another example where a lactose placebo was used in a gastrointestinal trial. Under the assumption that the lactose was harmful, why does this overstate the positive benefit of the treatment?<br />
<br />
3. Why is modern communication, e.g., the internet, facebook, etc., a cause for concern when conducting a randomized control trial (with or without a placebo arm)?<br />
<br />
4. Golomb further alleges, “failure to describe placebo ingredients breaches basic scientific standards of rigor.” Why would describing the placebo ingredients “disadvantage” the “publication prospects” of the researchers and “disadvantage” the publisher of the particular journal?<br />
<br />
5. Medicine is not the only area of endeavor which should require a placebo arm. Name some others.<br />
<br />
6. For the record, the term ''nocebo'' (I will harm) was coined in 1961 and refers to the negative effects of a sham or simulated medical intervention. An example sometimes given is a patient dying of fright due to being bitten by a non-poisonous snake. Give examples of some other nocebos.<br />
<br />
7. Why would prayer be considered a placebo? Why would prayer be considered a nocebo? A treatment?<br />
<br />
8. [http://www.startribune.com/lifestyle/faith/107497148.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUvckD8EQDUF Exorcism] has been in the news lately. Is exorcism a treatment, a placebo or a nocebo? <br />
<br />
9. Faith healing is always in the news. What distinguishes faith healing from exorcism from prayer? That is, why is prayer more commonly acceptable than either of the other two? <br />
<br />
Submitted by Paul Alper<br />
<br />
==Research is slow==<br />
<br />
[http://www.nytimes.com/2010/11/28/weekinreview/28mcneil.html An AIDS Advance, Hiding in the Open], <br />
Donald G. McNeil, Jr. The New York Times, November 27, 2010.<br />
<br />
The wheels of research machinery turn slowly. A recent article in the New York Times highlights some of the delays in obtaining data for a promising new drug for prevention of AIDS.<br />
<br />
<blockquote>Last week, a clinical trial showed that taking Truvada, a pill combining two drugs, once a day would greatly reduce a gay man’s chances of getting infected with the dangerous virus. Although confirmatory studies are still needed, the practice — called “pre-exposure prophylaxis,” or “prep” — will, in theory, also protect sex workers, needle sharers, wives of infected men, prison inmates and anyone else at risk.</blockquote><br />
<br />
Truvada is not a new drug, and indications of its promise and potential were known years ago. So why has it taken so long to obtain this data?<br />
<br />
<blockquote>The delay turns out to be a combination of scientific caution and the fiery politics of AIDS. While a medical advance can be made by a momentary flash of inspiration or luck — as legendarily happened with penicillin — proving that it works can take forever. And that is particularly true with AIDS, a disease surrounded by visceral fears, longstanding prejudices and the potential for huge profits.</blockquote><br />
<br />
Part of the problem has to do with the nature of prevention research.<br />
<br />
<blockquote>Giving powerful drugs to healthy people is different from giving them to the desperately ill. No doctor would give cancer drugs to a healthy person. Prophylaxis is common with, for example, malaria drugs for travelers making brief sojourns in the tropics. But a drug to be taken all one’s life — or at least for all of one’s sex life — must be very safe.</blockquote><br />
<br />
There is a legal barrier to prevention research as well.<br />
<br />
<blockquote>Another factor is that not every drug company wants to see its best treatment drugs, on which it earns billions of dollars, tested for prevention. Dying patients accept unpleasant side effects; healthy ones might sue.</blockquote><br />
<br />
And there were political pressures. AIDS activist groups stopped some earlier trials of Truvada.<br />
<br />
<blockquote>At the 2004 International AIDS Conference in Bangkok, the Paris chapter of the AIDS activist group Act-Up unexpectedly attacked Gilead Sciences’ booth, spraying it with fake blood and accusing the company of experimenting on poor people. As Dr. Jaffe tells it, French activists “played the anti-U.S. card in Francophone countries” and stirred up sex workers’ unions in Cambodia, eventually leading the Cameroonian and Cambodian governments to stop their trials. Nigeria’s stopped for other reasons, though many Nigerians were hostile to drug companies because of rumors that polio vaccine was an anti-Muslim plot and because Pfizer had tested a new antibiotic on children with meningitis. “If not for this misplaced activism, we might have had an answer five years earlier,” Dr. Jaffe said. </blockquote><br />
<br />
Another scientists sees the activism differently.<br />
<br />
<blockquote>Dr. Grant saw the same struggle differently. The activists were disruptive, he said, but also “raised significant questions” about whether participants would be protected from side effects and about who, if anyone, would pay for lifelong treatment if participants did eventually get AIDS. One result, he said, was that protocols were improved and more countries added: South Africa, Brazil, Peru, Ecuador, Thailand. But more important, he said, was the emergence of the two agencies that now pay for treatment in poor countries, the Global Fund to Fight AIDS, Tuberculosis and Malaria, and the President’s Emergency Plan for AIDS Relief. It took until about 2005 for most poor countries to take advantage of that aid. </blockquote><br />
<br />
===Questions===<br />
<br />
1. Does our legal system make it too easy for research participants to sue? What would be the consequences, both positive and negative, if such suits were barred or at least made more difficult to process?<br />
<br />
2. Do you view the involvement of the AIDS activist group, Act-Up, as a positive or negative influence on research?<br />
<br />
3. What safeguards are needed for clinical trials that are conducted in third world countries?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Statistics from the Victorian Era==<br />
<br />
[http://www.nytimes.com/2010/12/04/books/04victorian.html Analyzing Literature by Words and Numbers], Patricia Cohen, The New York Times, December 3, 2010.<br />
<br />
A recent effort by Google allows a statistical analysis of the Victorian era.<br />
<br />
<blockquote>The titles of every British book published in English in and around the 19th century — 1,681,161, to be exact — are being electronically scoured for key words and phrases that might offer fresh insight into the minds of the Victorians.</blockquote><br />
<br />
Here are some trends in the usage of words in these books:<br />
<br />
http://graphics8.nytimes.com/images/2010/12/04/books/04victorian-graphic/04victorian-graphic-popup.gif<br />
<br />
The research was made possible by Google, a fact that makes some scholars uneasy.<br />
<br />
<blockquote>Some scholars are wary of the control an enterprise like Google can exert over digital information. Google’s plan to create a voluminous online library and store has raised alarms about a potential monopoly over digital books and the hefty pricing that might follow.</blockquote><br />
<br />
Google is trying to avoid any controversy.<br />
<br />
<blockquote>But Jon Orwant, the engineering manager for Google Books, Magazines and Patents, said the plan was to make collections and searching tools available to libraries and scholars free. “That’s something we absolutely will do, and no, it’s not going to cost anything,” he said. </blockquote><br />
<br />
===Questions===<br />
<br />
1. What are some of the limitations to the use of word counts.<br />
<br />
2. What other applications besides historical studies could benefit from this database?<br />
<br />
Submitted by Steve Simon<br />
<br />
==The Truth Wears Out==<br />
The New Yorker<br><br />
December 13,2010, p.52<br><br />
[http://www.open.salon.com/blog/simoleonsense/2010/12/06/jonah_lehrer_when_truth_wears_off_aka_the_decline_effect Lehrer]<br><br />
The theme is failure of replication after initial "successful" trials<br><br />
Submitted by Dick Williamson<br />
<br />
==Survey says ...==<br />
From a review of Carol Graham’s <i>Happiness Around the World</i>, Oxford University Press, 2009,<br><br />
by Prashanth Ak in “Toward an Economy of Well-Being,” <i>Science</i>, August 6, 2010:<br />
<blockquote>To take one reason for caution, a good deal hinges on the order in which survey questions are posed. When undergraduates were asked how many dates they had the previous month followed by how happy they were with their lives in general, the correlation between the questions was high (r = 0.66). However, when the order of the questions was reversed, the correlation nearly vanished (r = –0.12).</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Just joking==<br />
From Patrick Vennebush’s blog[http://mathjokes4mathyfolks.wordpress.com/?s=statisti&searchbutton=Go!], <br />
<blockquote>A statistician’s wife gives birth to twins. Excitedly, he calls everyone to share the good news. When he calls the minister, the minister says, ‘That’s terrific! Bring them down to church this Sunday, and we’ll baptize them!’<br><br />
’Uh, let’s just baptize one of them,’ says the statistician. ‘We can keep the other one as a control.’</blockquote><br />
Vennebush is Online Project Manager for NCTM, father of twins, and author of <i>Math Jokes 4 Mathy Folks</i>.<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_69&diff=11525Chance News 692010-11-29T04:05:17Z<p>PaulAlper: /* Placebo contents */</p>
<hr />
<div>==Quotations==<br />
"The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true."<br />
<div align=right>John P.A. Ioannidis,<br />
in [http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.0020124 Why most published research findings are false]<br></div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
<br />
==Placebo contents==<br />
<br />
According to [http://en.wikipedia.org/wiki/Placebo Wikipedia], <br />
<blockquote><br />
A placebo (''Latin: I shall please'') is a sham or simulated medical intervention that can produce a (perceived or actual) improvement, called a placebo effect.<br />
<br />
[The origin for the term placebo] dates back to a Latin translation of the Bible by Jerome. It was first used in a medicinal context in the 18th century. In 1785 it was defined as a "commonplace method or medicine" and in 1811 it was defined as "any medicine adapted more to please than to benefit the patient," sometimes with a derogatory implication. <br />
</blockquote><br />
<br />
Nowadays, so entrenched is the necessity of a comparison to a placebo, any medical treatment trial without a control arm containing a placebo would be viewed skeptically both statistically and medicinally. But, consider the provocative title of [http://www.annals.org/content/153/8/532.abstract Golomb]: “What's in Placebos: Who Knows? Analysis of Randomized, Controlled Trials.” Surprisingly,<br />
<blockquote><br />
No regulations govern placebo composition. The composition of placebos can influence trial outcomes and merits reporting.<br />
</blockquote><br />
<br />
The study looked at four prestigious journals: ''New England Journal of Medicine'', ''JAMA'', ''The Lancet'' and ''Annals of Internal Medicine''. Included were 176 journal articles:<br />
<blockquote><br />
<br />
Most studies did not disclose the composition of the study placebo. Disclosure was less common for pills than for injections and other treatments (8.2% vs. 26.7%; P = 0.002).<br />
</blockquote><br />
<blockquote><br />
'''Conclusion''': Placebos were seldom described in randomized, controlled trials of pills or capsules. Because the nature of the placebo can influence trial outcomes, placebo formulation should be disclosed in reports of placebo-controlled trials.<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. Golomb cites the following example: “For instance, olive oil and corn oil have been used as the placebo in trials of cholesterol-lowering drugs.” Under the assumption that these oils might be beneficial, rather than inert, why does this understate the positive benefit of the treatment?<br />
<br />
2. Golomb cites another example where a lactose placebo was used in a gastrointestinal trial. Under the assumption that the lactose was harmful, why does this overstate the positive benefit of the treatment?<br />
<br />
3. Why is modern communication, e.g., the internet, facebook, etc., a cause for concern when conducting a randomized control trial (with or without a placebo arm)?<br />
<br />
4. Golomb further alleges, “failure to describe placebo ingredients breaches basic scientific standards of rigor.” Why would describing the placebo ingredients “disadvantage” the “publication prospects” of the researchers and “disadvantage” the publisher of the particular journal?<br />
<br />
5. Medicine is not the only area of endeavor which should require a placebo arm. Name some others.<br />
<br />
6. For the record, the term ''nocebo'' (I will harm) was coined in 1961 and refers to the negative effects of a sham or simulated medical intervention. An example sometimes given is a patient dying of fright due to being bitten by a non-poisonous snake. Give examples of some other nocebos.<br />
<br />
7. Why would prayer be considered a placebo? Why would prayer be considered a nocebo? A treatment?<br />
<br />
8. [http://www.startribune.com/lifestyle/faith/107497148.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUvckD8EQDUF Exorcism] has been in the news lately. Is exorcism as a treatment, a placebo or a nocebo? <br />
<br />
9. Faith healing is always in the news. What distinguishes faith healing from exorcism from prayer? That is, why is prayer more commonly acceptable than either of the other two? <br />
<br />
Submitted by Paul Alper<br />
<br />
==Item 2==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_69&diff=11521Chance News 692010-11-29T04:04:38Z<p>PaulAlper: /* Placebo contents */</p>
<hr />
<div>==Quotations==<br />
"The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true."<br />
<div align=right>John P.A. Ioannidis,<br />
in [http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.0020124 Why most published research findings are false]<br></div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
<br />
==Placebo contents==<br />
<br />
According to [http://en.wikipedia.org/wiki/Placebo Wikipedia], <br />
<blockquote><br />
A placebo (''Latin: I shall please'') is a sham or simulated medical intervention that can produce a (perceived or actual) improvement, called a placebo effect.<br />
<br />
[The origin for the term placebo] dates back to a Latin translation of the Bible by Jerome. It was first used in a medicinal context in the 18th century. In 1785 it was defined as a "commonplace method or medicine" and in 1811 it was defined as "any medicine adapted more to please than to benefit the patient," sometimes with a derogatory implication. <br />
</blockquote><br />
<br />
Nowadays, so entrenched is the necessity of a comparison to a placebo, any medical treatment trial without a control arm containing a placebo would be viewed skeptically both statistically and medicinally. But, consider the provocative title of [http://www.annals.org/content/153/8/532.abstract Golomb]: “What's in Placebos: Who Knows? Analysis of Randomized, Controlled Trials.” Surprisingly,<br />
<blockquote><br />
No regulations govern placebo composition. The composition of placebos can influence trial outcomes and merits reporting.<br />
</blockquote><br />
<br />
The study looked at four prestigious journals: ''New England Journal of Medicine'', ''JAMA'', ''The Lancet'' and ''Annals of Internal Medicine''. Included were 176 journal articles:<br />
<blockquote><br />
<br />
Most studies did not disclose the composition of the study placebo. Disclosure was less common for pills than for injections and other treatments (8.2% vs. 26.7%; P = 0.002).<br />
</blockquote><br />
<blockquote><br />
'''Conclusion''': Placebos were seldom described in randomized, controlled trials of pills or capsules. Because the nature of the placebo can influence trial outcomes, placebo formulation should be disclosed in reports of placebo-controlled trials.<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. Golomb cites the following example: “For instance, olive oil and corn oil have been used as the placebo in trials of cholesterol-lowering drugs.” Under the assumption that these oils might be beneficial, rather than inert, why does this understate the positive benefit of the treatment?<br />
<br />
2. Golomb cites another example where a lactose placebo was used in a gastrointestinal trial. Under the assumption that the lactose was harmful, why does this overstate the positive benefit of the treatment?<br />
<br />
3. Why is modern communication, e.g., the internet, facebook, etc., a cause for concern when conducting a randomized control trial (with or without a placebo arm)?<br />
<br />
4. Golomb further alleges, “failure to describe placebo ingredients breaches basic scientific standards of rigor.” Why would describing the placebo ingredients “disadvantage” the “publication prospects” of the researchers and “disadvantage” the publisher of the particular journal?<br />
<br />
5. Medicine is not the only area of endeavor which should require a placebo arm. Name some others.<br />
<br />
6. For the record, the term ''nocebo'' (I will harm) was coined in 1961 and refers to the negative effects of a sham or simulated medical intervention. An example sometimes given is a patient dying of fright due to being bitten by a non-poisonous snake. Give examples of some other nocebos.<br />
<br />
7. Why would prayer be considered a placebo? Why would prayer be considered a nocebo? A treatment?<br />
<br />
8. [http://www.startribune.com/lifestyle/faith/107497148.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUvckD8EQDUF Exorcism] has been in the news lately. Is exorcism as a treatment, a placebo or a nocebo? <br />
<br />
9. Faith healing is always in the news. What distinguishes faith healing from exorcism from prayer? That is, why is prayer more acceptable than either of the other two? <br />
<br />
Submitted by Paul Alper<br />
<br />
==Item 2==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_68&diff=11492Chance News 682010-11-11T16:16:16Z<p>PaulAlper: /* Walking and dementia */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>"If you're a politician, admitting you're wrong is a weakness, but if you're an engineer, you essentially want to be wrong half the time. If you do experiments and you're always right, then you aren't getting enough information out of those experiments. You want your experiment to be like the flip of a coin: You have no idea if it is going to come up heads or tails. You want to not know what the results are going to be." Peter Norvig, as quoted at [http://www.slate.com/blogs/blogs/thewrongstuff/archive/2010/08/03/error-message-google-research-director-peter-norvig-on-being-wrong.aspx Slate Magazine]. Submitted by Steve Simon.</blockquote><br />
<br />
-----<br />
Two quotes from Sir Francis Galton[http://www-history.mcs.st-and.ac.uk/Quotations/Galton.html]:<br />
<blockquote> “ I know of scarcely anything so apt to impress the imagination as the wonderful form of cosmic order expressed by the 'Law of Frequency of Error.' The law would have been personified by the Greeks and deified, if they had known of it. It reigns with serenity and in complete self-effacement, amidst the wildest confusion. The huger the mob, and the greater the apparent anarchy, the more perfect is its sway. It is the supreme law of Unreason. Whenever a large sample of chaotic elements are taken in hand and marshaled in the order of their magnitude, an unsuspected and most beautiful form of regularity proves to have been latent all along.”<br><br />
<br />
“[Statistics are] the only tools by which an opening may be cut through the formidable thicket of difficulties that bars the path of those who pursue the Science of Man.”</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Forsooth==<br />
A blogger responded to a John Allen Paulos article in <i>The New York Times</i> of October 24, 2010[http://opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/]:<br />
<blockquote>”One can't really say anything meaningful about probability without actual data.”</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<br />
==Paulos on probability==<br />
[http://opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/ “Stories vs. Statistics”]<br><br />
by John Allen Paulos, <i>The New York Times</i>, October 24, 2010<br><br />
<br />
In this article, Paulos discusses two classic probability problems, and 143 bloggers[http://community.nytimes.com/comments/opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/?sort=oldest]respond <i>en masse</i>.<br><br />
<br />
PROBLEM 1. With respect to the story of Linda the famous feminist bank teller, Paulos says that, while more details about a fictional character may make the story more believable, “the more details there are in a story, the less likely it is that the conjunction of all of them is true.”<br />
<br />
<blockquote>In the classic illustration of the fallacy …, a woman named Linda is described. She is single, in her early 30s, outspoken, and exceedingly smart. A philosophy major in college, she has devoted herself to issues such as nuclear non-proliferation. So which of the following is more likely?<br><br />
a.) Linda is a bank teller.<br><br />
b.) Linda is a bank teller and is active in the feminist movement.</blockquote><br />
Paulos concludes, “Although most people choose b.), this option is less likely since two conditions must be met in order for it to be satisfied, whereas only one of them is required for option a.) to be satisfied.”<br><br />
<br />
PROBLEM 1. Bloggers<br><br />
No. 10. a.) is not necessarily more likely than b.). Paulos’ “understanding of others is weak,” and we need more information about how her activism may have led to sexual discrimination to answer the question.<br><br />
No. 20’s response to #10. “Unless you believe that there could not possibly be such a person, Paulos is correct.”<br><br />
<br />
PROBLEM 2, with variations. With respect to the classic two-boy problem, Paulos says that “our judgment of [a] probability is almost always affected by its intensional [sic] context.”<br />
<blockquote>Given that a family has two children and that at least one of them is a boy, what is the probability that both children are boys? The most common solution notes that there are four equally likely possibilities — BB, BG, GB, GG …. Since we’re told that the family has at least one boy, the GG possibility is eliminated and only one of the remaining three equally likely possibilities is a family with two boys. Thus the probability of two boys in the family is 1/3. …. What if instead of being told that the family has at least one boy, we meet the parents who introduce us to their son? Then there are only two equally like possibilities — the other child is a girl or the other child is a boy, and so the probability of two boys is 1/2.</blockquote><br />
Paulos poses a “new variant of the two-boy problem”:<br />
<blockquote>A couple has two children and we’re told that at least one of them is a boy born on a Tuesday. What is the probability the couple has two boys? Believe it or not, the Tuesday is important, and the answer is 13/27. If we discover the Tuesday birth in slightly different intensional [sic] contexts, however, the answer could be 1/3 or 1/2.</blockquote><br />
PROBLEM 2, with variations. Bloggers<br><br />
No. 5. “[B]irth order is not part of the question, only whether the unidentified child is male or female, in which case the odds are 1 in 2 ….”<br><br />
No. 7. Settembrini gives the calculations for the 13/27 problem.<br><br />
No. 25, Ivan of NYC. “There is another version to the BG problem: suppose that in a family of two children, one is a girl named Emily. What is the probability that the other child is her sister? Turns out to be 1/2. (I was asked this question on an interview)”<br><br />
<br />
===Discussion===<br />
1. How would you respond to Blogger 10's comment about needing more information?<br><br />
2. With respect to blogger 20, suppose that you believe that there could not possibly be such a person as Linda. What would be the probability of a.)? The probability of b.)? Would Paulos be correct in this case?<br><br />
3. How would you respond to Blogger 5's comment about birth order?<br><br />
4. Without viewing Blogger 7’s calculations, calculate the answer to the 13/27 problem. Do you agree with Blogger 7's calculations?<br><br />
5. Do you agree with Blogger 25 about the probability when you know one child's name?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
===Comments===<br />
A reasonable explanation for the probability confusion alluded to in <br><br />
&nbsp;&nbsp;&nbsp; a.) Linda is a bank teller.<br><br />
&nbsp;&nbsp;&nbsp; b.) Linda is a bank teller and is active in the feminist movement.<br><br />
<br />
is that the language of logic and the language of English are not identical. For example, "Or" in logic means either X or Y or both,<br />
whereas "or" in English usually means the exclusive "Or" in logic, <br />
either X or Y but not both.<br />
<br />
When it comes to "and," the reader, when not misreading the "and" for "or," tends to substitute "who," so instead of<br />
X and Y,<br />
the reader is really considering <br />
X|Y<br />
which, depending on the reader's view of feminists and bank tellers, may or may not lead to the belief that (b) is more likely than (a). <br />
<br />
Submitted by Paul Alper<br />
<br />
<br />
<br />
==Facebook data on relationship breakups==<br />
<br />
[http://bits.blogs.nytimes.com/2010/11/03/using-facebook-updates-to-chronicle-breakups Using Facebook Updates to Chronicle Breakups], Nick Bilton, The New York Times Bits Blog, November 3, 2010.<br />
<br />
David McCandless has a hobby that many would find odd, but perhaps not too odd to readers of Chance News.<br />
<br />
<blockquote>David McCandless, a London-based author, writer and designer, is constantly playing with data sets available online and translating heaps of code into well-designed visual stories. Some of Mr. McCandless’s notable projects include visualizing the billions of dollars spent by people and governments around the world and visually explaining the different views of United States politicians, divided by their political predilection.</blockquote><br />
<br />
Facebook, a social network site, has data on relationship status: single, in a relationship, married, it's complicated, etc. With the help of Lee Byron of Facebook, he produced the following graph on breakups by looking at changes in relationship status.<br />
<br />
http://graphics8.nytimes.com/images/2010/11/03/technology/bits-breakupfbook/bits-breakupfbook-blogSpan.jpg<br />
<br />
The repeated peaks are Mondays, a day at higher risk of breakups. The general findings are that<br />
<br />
<blockquote>most breakups occur three times in the year — in the weeks leading up to spring breaks, right before the start of the summer holidays and a couple of weeks before Christmas.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Changing one's status in Facebook is a surrogate measure of the actual ending of a relationship. What limitations does this produce in this data set?<br />
<br />
2. Mr. McCandless claims that "people tend to break up with their significant others on Mondays, presumably after a weekend grapple." Is there an alternate explanation for the spike of breakups on Monday?<br />
<br />
Submitted by Steve Simon<br />
<br />
==National polling 2010==<br />
[http://www.huffingtonpost.com/2010/11/03/how-did-the-polls-do_n_778216.html “How Did The Polls Do?”]<br><br />
by Mark Blumenthal, <i>HUFFPOST POLLSTER</i>, November 3, 2010<br><br />
<br />
Blumenthal summarizes his initial impressions of the 2010 polling efforts:<br />
<blockquote>On average, the final statewide pre-election polls once again provided a largely unbiased measurement of the outcomes of most races, Congressional District polling had a slight Democratic skew, national polls that sampled both landline and cell phones measured national Congressional vote preference more accurately than those that sampled only landline phones and the venerable Gallup Poll took one on the chin. .... Gallup's error on the margin will likely be its biggest since it started asking the generic vote question 60 years ago.</blockquote><br />
<br />
http://images.huffingtonpost.com/2010-11-03-Blumenthal-Generic2Party1103.png<br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Nevada polling 2010==<br />
[http://www.huffingtonpost.com/2010/11/05/not-all-polls-were-wrong-_n_779705.html?view=screen “Not All Polls Were Wrong In Nevada”]<br><br />
By Mark Blumenthal, <i>HUFFPOST POLLSTER</i>, November 6, 2010<br><br />
<br />
<blockquote>While <i>public</i> media polls in late October consistently gave a slight advantage to Republican Senate challenger Sharron Angle, the <i>internal campaign</i> polls gave Democrat Harry Reid the edge and campaign pollsters on both sides attribute the difference to a combination of greater care in modeling the demographics of the electorate, more persistence in reaching all sampled voters and the added value of registered voter lists. [contributor's emphasis]</blockquote><br />
<br />
Candidate pollsters also attributed their successes to maintaining a <i>constant</i> model of the distribution of voters (by age, gender, race, region) across the surveys, having available rich data sets of past voter behavior, insisting on multiple callbacks to reach pre-identified but unavailable voters instead of relying on random-digit dialing or settling for phone answerers, and using hand-dialed cell phone numbers despite the additional work required. (Random-digit dialing to cell phones is banned by federal regulation.)<br><br />
<br />
===Discussion===<br />
1. Explain, and/or comment on, the following statement by the author:<br />
<blockquote>While none of the margins on any one poll was large enough to attain statistical significance, the consistency of the results demonstrates that Angle's advantages did not occur by chance alone.</blockquote><br />
2. Do you agree with this statement by the author?<br />
<blockquote>Our final "trend estimate" gave Angle a nearly three-point lead (48.8% to 46.0%) -- enough to classify the race as "lean Republican."</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Galton board video==<br />
[http://www.youtube.com/watch?v=AUSKTk9ENzg “Probability Machine”]<br><br />
<br />
This is a nice YouTube video showing how the action of beads falling through an assortment of pins resembles the behavior of 5,000-6,000 monthly returns of the IFA Index Portfolio 100 over 50 years (through 2008).<br><br />
<br />
There are three parts to the machine: (a) a fixed, drawn bell curve superimposed on glass over (b) a physical bar chart of thousands of beads representing the last 50 years of monthly average returns, and (c) a physical device randomly dropping beads through pins above the bar chart. A voiceover narrates the action of the falling beads, which is described as random.<br><br />
<br />
===Discussion===<br />
Comment on the following (spelling-edited) blogs[http://www.youtube.com/watch?v=AUSKTk9ENzg].<br><br />
<br />
1. “How is it random if all the beads are funneled into the center already. If a bead doesn’t start towards the right side, it’s never going to reach the right side.”<br><br />
<br />
2. “Random would be an even distribution across the board. Random implies NO PATTERN …but this is clearly a pattern.”<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Remarkable birthday pattern, or not?==<br />
[http://www.usatoday.com/yourlife/parenting-family/babies/2010-10-14-Birthday14_ST_N.htm “Mom’s babies born on 8-8-08, 9-9-09, 10-10-10”]<br><br />
by Elizabeth Weise, USA TODAY, October 14, 2010<br><br />
<br />
The article quotes a University of Oregon biostatistician: <br />
<blockquote>While the dates might seem “incredibly rare,” they're really not. Such a lineup can only happen in the first 12 years of the century and at least 10 months apart. …. Given that the first birth occurred in that window, the probability is not as astronomical as you might be compelled to think.</blockquote><br />
<br />
And a Berkeley statistician states:<br />
<blockquote>[I]t's not that high a number at all. …. The 'chance' you get depends on the assumptions you make. …. One set of assumptions gives a chance of about 1 in 50 million. More realistic assumptions — including allowing at least 11 months between births — increases it to about 1 in 2,500. Since thousands of women in the United States had kids in 2008, 2009 and 2010, this suddenly seems a little less extraordinary.</blockquote><br />
<br />
===Questions===<br />
1. Estimate the probability of these three birthdays, based on the Oregon professor’s statement. What other assumption(s), if any, did you need?<br><br />
2. Can you confirm the Berkeley statistician’s figure of 1 in 2,500, based on his "more realitic" assumption?<br><br />
3. How might the Berkeley statistician have arrived at the 1 in 50 million figure? What assumption(s) did you need?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Walking and dementia==<br />
<br />
As per usual, eye-popping headlines in the press and on the web can be misleading:<br />
<UL><br />
<li>[http://www.msnbc.msn.com/id/39657391/ns/health-alzheimer%27s_disease MSNBC:] “One way to ward off Alzheimer's: Take a hike” <br />
<li>[http://abcnews.go.com/Technology/wireStory?id=11873093 ABC News:] “Walking May Keep Brain From Shrinking in Old Age”<br />
<li>[http://punjabnewsline.com/content/walking-helps-retain-memory-old-age/24896 Punjab Newsline:] “Walking helps retain memory in old age” <br />
<li>[http://www.oregonlive.com/health/index.ssf/2010/10/forget_thinner_thighs_new_stud.html Oregon Live:] “Prime of life: Forget thinner thighs, new study shows walking protects brain size, saves memory”<br />
<li>[http://www.independent.co.uk/life-style/health-and-families/walking-can-save-your-memory-2120968.html Independent:] “Walking can save your memory”<br />
<li>[http://www.thirdage.com/news/alzheimer%E2%80%99s-disease-can-be-offset-walking_10-15-2010 Thirdage:] “Alzheimer’s Disease Can be Offset by Walking”<br />
</UL><br />
The research article on which this news coverage is based--Erickson, et al, “Physical activity predicts gray matter volume in late adulthood: The Cardiovascular Health Study”, ''Neurology'', first published on October 13, 2010--has more modest proclamations. <br />
<blockquote><br />
We cannot conclude a causal association between PA [physical activity] and GM [gray matter] volume.<br />
</blockquote><br />
<blockquote><br />
…given the observational nature of the study, we are unable to conclude that PA causes greater GM volume.<br />
</blockquote><br />
<blockquote><br />
Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment.<br />
</blockquote><br />
<br />
The study began in 1989-1990 with 1479 elderly subjects who “were free of dementia and mild cognitive impairment (MCI).” These subjects had their physical activity assessed at that time. In the nine years of follow-up, MRI’s were performed; this resulted in “299 cognitively normal subjects.” After four further years of follow-up, “183 remained cognitively normal in 2002-03” and “116 diagnosed MCI or dementia in 2002-03.” The authors chose to disaggregate the 299 into four groups depending on the number of blocks walked per week, 0-12, 13-24, 25-70 and 72-300 with 72 blocks being equated roughly to between 6 and 9 miles. The study claims that the last group had less gray matter shrinkage than any of the other three with no significant difference among the others.<br />
<br />
'''Discussion'''<br><br />
1. The data for the number of blocks walked per week were obtained by asking the participants. Why is this a problem?<br><br />
2. Why was tennis rejected as a measure of physical activity?<br><br />
3. The underlying belief is that walking has an effect on brain health. Defend the notion that brain health has an effect on the desire to walk. The authors put it this way: “there remains a possibility that reduced amounts of walking is a result of ill health and that ill health leads to both reduced amounts of walking and GM volume loss.”<br><br />
4. The original data were obtained in 1989-1990 and the final data occurred in 2002-03; the paper has ten authors and was published in 2010. What does this say about the difficulties of studying humans as opposed to fruit flies? <br><br />
5. According to [http://www.science20.com/news_articles/walking_6_miles_week_may_preserve_memory_old_age Science 2.0:] “The researchers found that those who walked the most cut their risk of developing memory problems in half.” Why is this “risk” a relative risk and not an absolute risk?<br><br />
6. The study does not show the percentage of cognitive impairment in each of the four walking categories. Why would this be helpful?<br><br />
7. The statement found in the Conclusion,<br />
"Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment"<br />
hints, via the concept of transitivity, that greater amounts of walking is associated with a reduced risk of cognitive impairment. That is, if A is related to B and B is related to C, then A is related to C. However, see [http://www.jstor.org/pss/2685695 Langford, et. al.] for a discussion of why this is not true in general. In particular, here is one of their counterexamples:<br />
<br />
<center><br />
{| border="1" style="text-align:center" cellpadding="3"<br />
! X !! Y !! Z <br />
|-<br />
|4 || 201 || 15 <br />
|-<br />
| 6 || 165 || 30<br />
|-<br />
| 1 || 145 || 28 <br />
|-<br />
| 1 || 150 || 41 <br />
|-<br />
| 0 || 160 || 18 <br />
|-<br />
|2 || 113 || 5<br />
|-<br />
|5 || 140 || 7<br />
|-<br />
|4 || 147 || 16<br />
|-<br />
|0 || 83 || 15<br />
|-<br />
|0 || 108 || 16<br />
|}<br />
</center><br />
<br />
Use a stats package to show that even though the correlation between X and Y is positive, and the correlation between Y and Z is positive, but the correlation between X and Z is negative.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_68&diff=11485Chance News 682010-11-10T05:00:27Z<p>PaulAlper: /* Walking and dementia */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>"If you're a politician, admitting you're wrong is a weakness, but if you're an engineer, you essentially want to be wrong half the time. If you do experiments and you're always right, then you aren't getting enough information out of those experiments. You want your experiment to be like the flip of a coin: You have no idea if it is going to come up heads or tails. You want to not know what the results are going to be." Peter Norvig, as quoted at [http://www.slate.com/blogs/blogs/thewrongstuff/archive/2010/08/03/error-message-google-research-director-peter-norvig-on-being-wrong.aspx Slate Magazine]. Submitted by Steve Simon.</blockquote><br />
<br />
-----<br />
Two quotes from Sir Francis Galton[http://www-history.mcs.st-and.ac.uk/Quotations/Galton.html]:<br />
<blockquote> “ I know of scarcely anything so apt to impress the imagination as the wonderful form of cosmic order expressed by the 'Law of Frequency of Error.' The law would have been personified by the Greeks and deified, if they had known of it. It reigns with serenity and in complete self-effacement, amidst the wildest confusion. The huger the mob, and the greater the apparent anarchy, the more perfect is its sway. It is the supreme law of Unreason. Whenever a large sample of chaotic elements are taken in hand and marshaled in the order of their magnitude, an unsuspected and most beautiful form of regularity proves to have been latent all along.”<br><br />
<br />
“[Statistics are] the only tools by which an opening may be cut through the formidable thicket of difficulties that bars the path of those who pursue the Science of Man.”</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Forsooth==<br />
A blogger responded to a John Allen Paulos article in <i>The New York Times</i> of October 24, 2010[http://opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/]:<br />
<blockquote>”One can't really say anything meaningful about probability without actual data.”</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<br />
==Paulos on probability==<br />
[http://opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/ “Stories vs. Statistics”]<br><br />
by John Allen Paulos, <i>The New York Times</i>, October 24, 2010<br><br />
<br />
In this article, Paulos discusses two classic probability problems, and 143 bloggers[http://community.nytimes.com/comments/opinionator.blogs.nytimes.com/2010/10/24/stories-vs-statistics/?sort=oldest]respond <i>en masse</i>.<br><br />
<br />
PROBLEM 1. With respect to the story of Linda the famous feminist bank teller, Paulos says that, while more details about a fictional character may make the story more believable, “the more details there are in a story, the less likely it is that the conjunction of all of them is true.”<br />
<br />
<blockquote>In the classic illustration of the fallacy …, a woman named Linda is described. She is single, in her early 30s, outspoken, and exceedingly smart. A philosophy major in college, she has devoted herself to issues such as nuclear non-proliferation. So which of the following is more likely?<br><br />
a.) Linda is a bank teller.<br><br />
b.) Linda is a bank teller and is active in the feminist movement.</blockquote><br />
Paulos concludes, “Although most people choose b.), this option is less likely since two conditions must be met in order for it to be satisfied, whereas only one of them is required for option a.) to be satisfied.”<br><br />
<br />
PROBLEM 1. Bloggers<br><br />
No. 10. a.) is not necessarily more likely than b.). Paulos’ “understanding of others is weak,” and we need more information about how her activism may have led to sexual discrimination to answer the question.<br><br />
No. 20’s response to #10. “Unless you believe that there could not possibly be such a person, Paulos is correct.”<br><br />
<br />
PROBLEM 2, with variations. With respect to the classic two-boy problem, Paulos says that “our judgment of [a] probability is almost always affected by its intensional [sic] context.”<br />
<blockquote>Given that a family has two children and that at least one of them is a boy, what is the probability that both children are boys? The most common solution notes that there are four equally likely possibilities — BB, BG, GB, GG …. Since we’re told that the family has at least one boy, the GG possibility is eliminated and only one of the remaining three equally likely possibilities is a family with two boys. Thus the probability of two boys in the family is 1/3. …. What if instead of being told that the family has at least one boy, we meet the parents who introduce us to their son? Then there are only two equally like possibilities — the other child is a girl or the other child is a boy, and so the probability of two boys is 1/2.</blockquote><br />
Paulos poses a “new variant of the two-boy problem”:<br />
<blockquote>A couple has two children and we’re told that at least one of them is a boy born on a Tuesday. What is the probability the couple has two boys? Believe it or not, the Tuesday is important, and the answer is 13/27. If we discover the Tuesday birth in slightly different intensional [sic] contexts, however, the answer could be 1/3 or 1/2.</blockquote><br />
PROBLEM 2, with variations. Bloggers<br><br />
No. 5. “[B]irth order is not part of the question, only whether the unidentified child is male or female, in which case the odds are 1 in 2 ….”<br><br />
No. 7. Settembrini gives the calculations for the 13/27 problem.<br><br />
No. 25, Ivan of NYC. “There is another version to the BG problem: suppose that in a family of two children, one is a girl named Emily. What is the probability that the other child is her sister? Turns out to be 1/2. (I was asked this question on an interview)”<br><br />
<br />
===Discussion===<br />
1. How would you respond to Blogger 10's comment about needing more information?<br><br />
2. With respect to blogger 20, suppose that you believe that there could not possibly be such a person as Linda. What would be the probability of a.)? The probability of b.)? Would Paulos be correct in this case?<br><br />
3. How would you respond to Blogger 5's comment about birth order?<br><br />
4. Without viewing Blogger 7’s calculations, calculate the answer to the 13/27 problem. Do you agree with Blogger 7's calculations?<br><br />
5. Do you agree with Blogger 25 about the probability when you know one child's name?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
===Comments===<br />
A reasonable explanation for the probability confusion alluded to in <br><br />
&nbsp;&nbsp;&nbsp; a.) Linda is a bank teller.<br><br />
&nbsp;&nbsp;&nbsp; b.) Linda is a bank teller and is active in the feminist movement.<br><br />
<br />
is that the language of logic and the language of English are not identical. For example, "Or" in logic means either X or Y or both,<br />
whereas "or" in English usually means the exclusive "Or" in logic, <br />
either X or Y but not both.<br />
<br />
When it comes to "and," the reader, when not misreading the "and" for "or," tends to substitute "who," so instead of<br />
X and Y,<br />
the reader is really considering <br />
X|Y<br />
which, depending on the readers view of feminists and bank tellers, may or may not lead to the belief that (b) is more likely than (a). <br />
<br />
Submitted by Paul Alper<br />
<br />
==Student learning lags over summers==<br />
[http://www.time.com/time/nation/article/0,8599,2005654,00.html “The Case Against Summer Vacation”]<br><br />
by David Von Drehle, <i>TIME</i>, Thursday, July 22, 2010<br><br />
<br />
This article describes research about the effect on learning of long summer vacations for U.S. school children, especially for, but not limited to, low-income children without access to activities such as camp, travel, or other enrichment experiences. <br />
<blockquote>[W]hen American students are competing with children around the world, who are in many cases spending four weeks longer in school each year, larking through summer is a luxury we can't afford. …. By the time the bell rings on a new school year, the poorer kids have fallen weeks, if not months, behind. And even well-off American students may be falling behind their peers around the world. …. "We expect that athletes and musicians would see their performance suffer without practice. Well, the same is true of students, [says one educational administrator]."</blockquote><br />
The article provides two graphics, neither of which is online now. The first was a time-series graph showing the gap among low-, middle-, and high-income math test scores over grades 1 through 5; the contributor (cibesm@comcast.net) has an electronic copy for interested readers. The second was a bar chart containing the following data. (No information was given about the instrument on which the math scores were based or the number of students who were tested in each country.)<br><br />
<br />
Country-School Year (median days)-Total Instructional Hours-Math Scores (15-year-olds)<br><br />
South Korea-204-545-547<br><br />
Japan-200-600-523<br><br />
Denmark-200-648-513<br><br />
Brazil-200-800-370<br><br />
Mexico-200-1047-406<br><br />
Australia-197-815-520<br><br />
New Zealand-194-968-522<br><br />
Germany-193-758-504<br><br />
Norway-190-654-490<br><br />
U.S.-180-1080-474<br><br />
Luxembourg-176-642-490<br><br />
Spain-176-713-480<br><br />
Russia-169-845-476<br><br />
Italy-167-601-462<br><br />
===Questions===<br />
For each country, assume that similarly large numbers of students in each country took a common math test and that median days in a school year was a pretty accurate representation of the length of the school year across that country.<br> <br />
<br />
1. Given that the correlation between median days in a school year and total instructional hours is about -0.007, what might you conclude about the relationship between days and hours in a school year? Suggest an explanation for this.<br><br />
<br />
2. Sketch a graph of median days in a school year as the explanatory variable and math scores as the response variable.<br><br />
a. The data points for which two countries fall outside of the relatively linear pattern of the other twelve countries?<br><br />
b. Without those two data points, the correlation increases from about +0.108 to about +0.919. Can you think of any legitimate reason to omit them in order to report (with an appropriate note) a stronger correlation? What else might you want to know in order to decide?<br><br />
c. The author suggests that spending 4 weeks longer in school might improve U.S. math scores. Do you see any evidence <i>here</i> that extending the U.S. school year by 4 weeks (20 school days) would improve U.S. math scores?<br> <br />
<br />
3. Given that the correlation between total instructional hours and math scores is about -0.397, what does this <i>number alone</i> imply about the relationship between hours in a school year and math scores? Do you see any evidence <i>here</i> that increasing hours would improve U.S. math scores?<br><br />
<br />
4. For each country, a blogger calculated the total instructional hours of teaching required to increase a math score by 1 point and concluded, “The US is more efficient in its teaching then Mexico and Brazil.”<br><br />
a. The U.S. has more instructional hours per point than most other countries shown. Do you agree that this higher ratio indicates more "efficiency"?<br><br />
b. Do you agree with the blogger’s arithmetic with respect to his ordering of the U.S., Mexico, and Brazil ratios?<br><br />
c. What, if anything, might the U.S. rank with respect to these ratios suggest about U.S. teachers and/or students, compared to those of other countries?<br />
<br />
5. What other information and/or data might be helpful to decision-makers considering a decision about increasing the length of the U.S. school year?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Facebook data on relationship breakups==<br />
<br />
[http://bits.blogs.nytimes.com/2010/11/03/using-facebook-updates-to-chronicle-breakups Using Facebook Updates to Chronicle Breakups], Nick Bilton, The New York Times Bits Blog, November 3, 2010.<br />
<br />
David McCandless has a hobby that many would find odd, but perhaps not too odd to readers of Chance News.<br />
<br />
<blockquote>David McCandless, a London-based author, writer and designer, is constantly playing with data sets available online and translating heaps of code into well-designed visual stories. Some of Mr. McCandless’s notable projects include visualizing the billions of dollars spent by people and governments around the world and visually explaining the different views of United States politicians, divided by their political predilection.</blockquote><br />
<br />
Facebook, a social network site, has data on relationship status: single, in a relationship, married, it's complicated, etc. With the help of Lee Byron of Facebook, he produced the following graph on breakups by looking at changes in relationship status.<br />
<br />
http://graphics8.nytimes.com/images/2010/11/03/technology/bits-breakupfbook/bits-breakupfbook-blogSpan.jpg<br />
<br />
The repeated peaks are Mondays, a day at higher risk of breakups. The general findings are that<br />
<br />
<blockquote>most breakups occur three times in the year — in the weeks leading up to spring breaks, right before the start of the summer holidays and a couple of weeks before Christmas.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Changing one's status in Facebook is a surrogate measure of the actual ending of a relationship. What limitations does this produce in this data set?<br />
<br />
2. Mr. McCandless claims that "people tend to break up with their significant others on Mondays, presumably after a weekend grapple." Is there an alternate explanation for the spike of breakups on Monday?<br />
<br />
Submitted by Steve Simon<br />
<br />
==National polling 2010==<br />
[http://www.huffingtonpost.com/2010/11/03/how-did-the-polls-do_n_778216.html “How Did The Polls Do?”]<br><br />
by Mark Blumenthal, <i>HUFFPOST POLLSTER</i>, November 3, 2010<br><br />
<br />
Blumenthal summarizes his initial impressions of the 2010 polling efforts:<br />
<blockquote>On average, the final statewide pre-election polls once again provided a largely unbiased measurement of the outcomes of most races, Congressional District polling had a slight Democratic skew, national polls that sampled both landline and cell phones measured national Congressional vote preference more accurately than those that sampled only landline phones and the venerable Gallup Poll took one on the chin. .... Gallup's error on the margin will likely be its biggest since it started asking the generic vote question 60 years ago.</blockquote><br />
<br />
http://images.huffingtonpost.com/2010-11-03-Blumenthal-Generic2Party1103.png<br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Nevada polling 2010==<br />
[http://www.huffingtonpost.com/2010/11/05/not-all-polls-were-wrong-_n_779705.html?view=screen “Not All Polls Were Wrong In Nevada”]<br><br />
By Mark Blumenthal, <i>HUFFPOST POLLSTER</i>, November 6, 2010<br><br />
<br />
<blockquote>While <i>public</i> media polls in late October consistently gave a slight advantage to Republican Senate challenger Sharron Angle, the <i>internal campaign</i> polls gave Democrat Harry Reid the edge and campaign pollsters on both sides attribute the difference to a combination of greater care in modeling the demographics of the electorate, more persistence in reaching all sampled voters and the added value of registered voter lists. [contributor's emphasis]</blockquote><br />
<br />
Candidate pollsters also attributed their successes to maintaining a <i>constant</i> model of the distribution of voters (by age, gender, race, region) across the surveys, having available rich data sets of past voter behavior, insisting on multiple callbacks to reach pre-identified but unavailable voters instead of relying on random-digit dialing or settling for phone answerers, and using hand-dialed cell phone numbers despite the additional work required. (Random-digit dialing to cell phones is banned by federal regulation.)<br><br />
<br />
===Discussion===<br />
1. Explain, and/or comment on, the following statement by the author:<br />
<blockquote>While none of the margins on any one poll was large enough to attain statistical significance, the consistency of the results demonstrates that Angle's advantages did not occur by chance alone.</blockquote><br />
2. Do you agree with this statement by the author?<br />
<blockquote>Our final "trend estimate" gave Angle a nearly three-point lead (48.8% to 46.0%) -- enough to classify the race as "lean Republican."</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Galton board video==<br />
[http://www.youtube.com/watch?v=AUSKTk9ENzg “Probability Machine”]<br><br />
<br />
This is a nice YouTube video showing how the action of beads falling through an assortment of pins resembles the behavior of 5,000-6,000 monthly returns of the IFA Index Portfolio 100 over 50 years (through 2008).<br><br />
<br />
There are three parts to the machine: (a) a fixed, drawn bell curve superimposed on glass over (b) a physical bar chart of thousands of beads representing the last 50 years of monthly average returns, and (c) a physical device randomly dropping beads through pins above the bar chart. A voiceover narrates the action of the falling beads, which is described as random.<br><br />
<br />
===Discussion===<br />
Comment on the following (spelling-edited) blogs[http://www.youtube.com/watch?v=AUSKTk9ENzg].<br><br />
<br />
1. “How is it random if all the beads are funneled into the center already. If a bead doesn’t start towards the right side, it’s never going to reach the right side.”<br><br />
<br />
2. “Random would be an even distribution across the board. Random implies NO PATTERN …but this is clearly a pattern.”<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Remarkable birthday pattern, or not?==<br />
[http://www.usatoday.com/yourlife/parenting-family/babies/2010-10-14-Birthday14_ST_N.htm “Mom’s babies born on 8-8-08, 9-9-09, 10-10-10”]<br><br />
by Elizabeth Weise, USA TODAY, October 14, 2010<br><br />
<br />
The article quotes a University of Oregon biostatistician: <br />
<blockquote>While the dates might seem “incredibly rare,” they're really not. Such a lineup can only happen in the first 12 years of the century and at least 10 months apart. …. Given that the first birth occurred in that window, the probability is not as astronomical as you might be compelled to think.</blockquote><br />
<br />
And a Berkeley statistician states:<br />
<blockquote>[I]t's not that high a number at all. …. The 'chance' you get depends on the assumptions you make. …. One set of assumptions gives a chance of about 1 in 50 million. More realistic assumptions — including allowing at least 11 months between births — increases it to about 1 in 2,500. Since thousands of women in the United States had kids in 2008, 2009 and 2010, this suddenly seems a little less extraordinary.</blockquote><br />
<br />
===Questions===<br />
1. Estimate the probability of these three birthdays, based on the Oregon professor’s statement. What other assumption(s), if any, did you need?<br><br />
2. Can you confirm the Berkeley statistician’s figure of 1 in 2,500, based on his "more realitic" assumption?<br><br />
3. How might the Berkeley statistician have arrived at the 1 in 50 million figure? What assumption(s) did you need?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Walking and dementia==<br />
<br />
As per usual, eye-popping headlines in the press and on the web can be misleading:<br />
<UL><br />
<li>[http://www.msnbc.msn.com/id/39657391/ns/health-alzheimer%27s_disease MSNBC:] “One way to ward off Alzheimer's: Take a hike” <br />
<li>[http://abcnews.go.com/Technology/wireStory?id=11873093 ABC News:] “Walking May Keep Brain From Shrinking in Old Age”<br />
<li>[http://punjabnewsline.com/content/walking-helps-retain-memory-old-age/24896 Punjab Newsline:] “Walking helps retain memory in old age” <br />
<li>[http://www.oregonlive.com/health/index.ssf/2010/10/forget_thinner_thighs_new_stud.html Oregon Live:] “Prime of life: Forget thinner thighs, new study shows walking protects brain size, saves memory”<br />
<li>[http://www.independent.co.uk/life-style/health-and-families/walking-can-save-your-memory-2120968.html Independent:] “Walking can save your memory”<br />
<li>[http://www.thirdage.com/news/alzheimer%E2%80%99s-disease-can-be-offset-walking_10-15-2010 Thirdage:] “Alzheimer’s Disease Can be Offset by Walking”<br />
</UL><br />
The research article on which this news coverage is based--Erickson, et al, “Physical activity predicts gray matter volume in late adulthood: The Cardiovascular Health Study”, ''Neurology'', first published on October 13, 2010--has more modest proclamations. <br />
<blockquote><br />
We cannot conclude a causal association between PA [physical activity] and GM [gray matter] volume.<br />
</blockquote><br />
<blockquote><br />
…given the observational nature of the study, we are unable to conclude that PA causes greater GM volume.<br />
</blockquote><br />
<blockquote><br />
Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment.<br />
</blockquote><br />
<br />
The study began in 1998-1990 with 1479 elderly subjects who “were free of dementia and mild cognitive impairment (MCI).” These subjects had their physical activity assessed at that time. In the nine years of follow-up, MRI’s were performed; this resulted in “299 cognitively normal subjects.” After four further years of follow-up, “183 remained cognitively normal in 2002-03” and “116 diagnosed MCI or dementia in 2002-03.” The authors chose to disaggregate the 299 into four groups depending on the number of blocks walked per week, 0-12, 13-24, 25-70 and 72-300 with 72 blocks being equated roughly to between 6 and 9 miles. The study claims that the last group had less gray matter shrinkage than any of the other three with no significant difference among the others.<br />
<br />
'''Discussion'''<br><br />
1. The data for the number of blocks walked per week were obtained by asking the participants. Why is this a problem?<br><br />
2. Why was tennis rejected as a measure of physical activity?<br><br />
3. The underlying belief is that walking has an effect on brain health. Defend the notion that brain health has an effect on the desire to walk. The authors put it this way: “there remains a possibility that reduced amounts of walking is a result of ill health and that ill health leads to both reduced amounts of walking and GM volume loss.”<br><br />
4. The original data were obtained in 1989-1990 and the final data occurred in 2002-03; the paper has ten authors and was published in 2010. What does this say about the difficulties of studying humans as opposed to fruit flies? <br><br />
5. According to [http://www.science20.com/news_articles/walking_6_miles_week_may_preserve_memory_old_age Science 2.0:] “The researchers found that those who walked the most cut their risk of developing memory problems in half.” Why is this “risk” a relative risk and not an absolute risk?<br><br />
6. The study does not show the percentage of cognitive impairment in each of the four walking categories. Why would this be helpful?<br><br />
7. The statement found in the Conclusion,<br />
"Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment"<br />
hints, via the concept of transitivity, that greater amounts of walking is associated with a reduced risk of cognitive impairment. That is, if A is related to B and B is related to C, then A is related to C. However, see [http://www.jstor.org/pss/2685695 Langford] for a discussion of why this is not true in general. In particular, here is one of its counterexamples:<br />
<br />
<center><br />
{| border="1" style="text-align:center" cellpadding="3"<br />
! X !! Y !! Z <br />
|-<br />
|4 || 201 || 15 <br />
|-<br />
| 6 || 165 || 30<br />
|-<br />
| 1 || 145 || 28 <br />
|-<br />
| 1 || 150 || 41 <br />
|-<br />
| 0 || 160 || 18 <br />
|-<br />
|2 || 113 || 5<br />
|-<br />
|5 || 140 || 7<br />
|-<br />
|4 || 147 || 16<br />
|-<br />
|0 || 83 || 15<br />
|-<br />
|0 || 108 || 16<br />
|}<br />
</center><br />
<br />
Use a stats package to show that even though the correlation between X and Y is positive, and the correlation between Y and Z is positive, but the correlation between X and Z is negative.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11282Chance News 672010-10-09T19:53:35Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
An article describes two brands of athletic wear that are claimed to optimize performance via embedded holograms (Power Balance) and water-soluble titanium (Phiten).<br />
<blockquote>“A lot of these products are a sort of merchandized superstition. …. [A French surfer states,] ‘But if wearing the thing makes you think you feel or perform better, who cares?’”<br><br />
<div align="right"><br />
[http://www.time.com/time/magazine/article/0,9171,2021057,00.html “Wrist Watch”], <i>TIME</i>, October 4, 2010<br />
</div><br />
</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>”A scant 1,391 people live in 91008 ZIP code, and only 12 homes are currently on the market. So a single high-priced listing (like the mammoth nine-bedroom, built this year, that's selling for $19.8 million) is enough to skew the median price skyward.”<br><br />
<div align="right">[http://realestate.yahoo.com/promo/americas-most-expensive-zip-codes-2010.html America’s Most Expensive ZIP Codes 2010”], <br><i>Yahoo! Real Estate</i>, September 27, 2010<br />
</div></blockquote><br />
Note that someone at Forbes must have spotted the potential error in the last 8 words. While the original sentence remains on the Yahoo website, the sentence now ends “may not adequately represent how everyone in the area lives” at the Forbes website[http://www.forbes.com/2010/09/27/most-expensive-zip-codes-2010-lifestyle-real-estate-zip-codes-10-intro.html].<br><br />
<br />
Submitted by Margaret Cibes at the suggestion of Cris Wellington<br />
<br />
----<br />
<blockquote><br />
"The relationship between an area's income and mortality is so striking," the report says, "that on average, every $10,000 increase in an area's median income appears to buy its residents another year of life."<br />
<br><br />
<div align="right"> <br />
[http://www.startribune.com/lifestyle/health/104540289.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUs Key to long life? It may be in ... your ZIP code]<br>Minneapolis Star Tribune, 7 October 2010 </div><br />
</blockquote><br />
<br />
Submitted by Paul Alper<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to the Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department."<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he discusses systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 120 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorney's claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Sampling saliva==<br />
[http://www.thenation.com/article/154596/freshmen-specimen “Freshmen Specimen”]<br><br />
by Patricia J. Williams, <i>The Nation</i>, September 27, 2010<br> <br />
<br />
In this column, law professor Williams describes reactions to the University of California’s Berkeley project [http://onthesamepage.berkeley.edu/ “Bring Your Genes to Cal”], in which 5500 incoming freshmen were asked to provide saliva samples for the purpose of “bring[ing] the student body together in the same manner that reading To Kill a Mockingbird might have in the past.” More than 700 students submitted their samples to an uncertified Berkeley lab, and the samples were analyzed for “susceptibility to alcoholism, lactose intolerance and relative metabolism of folic acid.”<br><br />
<br />
<blockquote>[T]he California Department of Public Health barred the university from dispensing individual profiles on the grounds that genetic analysis is correlative only and is neither necessarily predictive nor diagnostic at this point. A collective comparison of the class's genetic data was permitted, however, and circulated in "anonymized" form at orientation.</blockquote><br />
<br />
Some ethical issues that have been raised include:<br><br />
(a) privacy, despite the “anonymizing” of results;<br><br />
(b) ownership of the data with respect to commercialization, patentability, remuneration, etc.;<br><br />
(c) promotion of the concept that a genetic correlation is a “100 percent infallible guarantee” of anything;<br><br />
(d) motive with respect to promoting sales of swab kits.<br><br />
<br />
The article refers to a Stanford University medical school class “spit party” and to a University of Minnesota [http://www.peds.umn.edu/gopherkids/ "Gopher Kids"] program (free gifts for saliva swabs at a state fair).<br />
<br />
Readers might be interested in a paper from ETC Group, a Canadian-based international organization, [http://www.etcgroup.org/upload/publication/675/02/genomixspitkits_03march08.pdf "Direct-to-Consumer DNA Testing and the Myth of Personalized Medicine: Spit Kits, SNP Chips and Human Genomics"]. Or they might want to google "spit party" to see how widespread these activities are.<br />
<br />
===Discussion===<br />
<br />
1. Explain what the Public Health Department meant by the clause "genetic analysis is correlative only." <br />
<br />
2. Comment on the following statement in the article: “The university advertises participation as altruistic, a contribution to public health and human knowledge.”<br><br />
<br />
3. The author of the article refers to the process of collecting saliva samples as a “commodity exchange.” Do you agree with the author?<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11281Chance News 672010-10-09T19:51:46Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
An article describes two brands of athletic wear that are claimed to optimize performance via embedded holograms (Power Balance) and water-soluble titanium (Phiten).<br />
<blockquote>“A lot of these products are a sort of merchandized superstition. …. [A French surfer states,] ‘But if wearing the thing makes you think you feel or perform better, who cares?’”<br><br />
<div align="right"><br />
[http://www.time.com/time/magazine/article/0,9171,2021057,00.html “Wrist Watch”], <i>TIME</i>, October 4, 2010<br />
</div><br />
</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>”A scant 1,391 people live in 91008 ZIP code, and only 12 homes are currently on the market. So a single high-priced listing (like the mammoth nine-bedroom, built this year, that's selling for $19.8 million) is enough to skew the median price skyward.”<br><br />
<div align="right">[http://realestate.yahoo.com/promo/americas-most-expensive-zip-codes-2010.html America’s Most Expensive ZIP Codes 2010”], <br><i>Yahoo! Real Estate</i>, September 27, 2010<br />
</div></blockquote><br />
Note that someone at Forbes must have spotted the potential error in the last 8 words. While the original sentence remains on the Yahoo website, the sentence now ends “may not adequately represent how everyone in the area lives” at the Forbes website[http://www.forbes.com/2010/09/27/most-expensive-zip-codes-2010-lifestyle-real-estate-zip-codes-10-intro.html].<br><br />
<br />
Submitted by Margaret Cibes at the suggestion of Cris Wellington<br />
<br />
----<br />
<blockquote><br />
"The relationship between an area's income and mortality is so striking," the report says, "that on average, every $10,000 increase in an area's median income appears to buy its residents another year of life."<br />
<br><br />
<div align="right"> <br />
[http://www.startribune.com/lifestyle/health/104540289.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUs Key to long life? It may be in ... your ZIP code]<br>Minneapolis Star Tribune, 7 October 2010 </div><br />
</blockquote><br />
<br />
Submitted by Paul Alper<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to the Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department."<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 120 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorney's claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Sampling saliva==<br />
[http://www.thenation.com/article/154596/freshmen-specimen “Freshmen Specimen”]<br><br />
by Patricia J. Williams, <i>The Nation</i>, September 27, 2010<br> <br />
<br />
In this column, law professor Williams describes reactions to the University of California’s Berkeley project [http://onthesamepage.berkeley.edu/ “Bring Your Genes to Cal”], in which 5500 incoming freshmen were asked to provide saliva samples for the purpose of “bring[ing] the student body together in the same manner that reading To Kill a Mockingbird might have in the past.” More than 700 students submitted their samples to an uncertified Berkeley lab, and the samples were analyzed for “susceptibility to alcoholism, lactose intolerance and relative metabolism of folic acid.”<br><br />
<br />
<blockquote>[T]he California Department of Public Health barred the university from dispensing individual profiles on the grounds that genetic analysis is correlative only and is neither necessarily predictive nor diagnostic at this point. A collective comparison of the class's genetic data was permitted, however, and circulated in "anonymized" form at orientation.</blockquote><br />
<br />
Some ethical issues that have been raised include:<br><br />
(a) privacy, despite the “anonymizing” of results;<br><br />
(b) ownership of the data with respect to commercialization, patentability, remuneration, etc.;<br><br />
(c) promotion of the concept that a genetic correlation is a “100 percent infallible guarantee” of anything;<br><br />
(d) motive with respect to promoting sales of swab kits.<br><br />
<br />
The article refers to a Stanford University medical school class “spit party” and to a University of Minnesota [http://www.peds.umn.edu/gopherkids/ "Gopher Kids"] program (free gifts for saliva swabs at a state fair).<br />
<br />
Readers might be interested in a paper from ETC Group, a Canadian-based international organization, [http://www.etcgroup.org/upload/publication/675/02/genomixspitkits_03march08.pdf "Direct-to-Consumer DNA Testing and the Myth of Personalized Medicine: Spit Kits, SNP Chips and Human Genomics"]. Or they might want to google "spit party" to see how widespread these activities are.<br />
<br />
===Discussion===<br />
<br />
1. Explain what the Public Health Department meant by the clause "genetic analysis is correlative only." <br />
<br />
2. Comment on the following statement in the article: “The university advertises participation as altruistic, a contribution to public health and human knowledge.”<br><br />
<br />
3. The author of the article refers to the process of collecting saliva samples as a “commodity exchange.” Do you agree with the author?<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11279Chance News 672010-10-07T14:55:10Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
An article describes two brands of athletic wear that are claimed to optimize performance via embedded holograms (Power Balance) and water-soluble titanium (Phiten).<br />
<blockquote>“A lot of these products are a sort of merchandized superstition. …. [A French surfer states,] ‘But if wearing the thing makes you think you feel or perform better, who cares?’”<br><br />
[http://www.time.com/time/magazine/article/0,9171,2021057,00.html “Wrist Watch”], <i>TIME</i>, October 4, 2010</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>”A scant 1,391 people live in 91008 ZIP code, and only 12 homes are currently on the market. So a single high-priced listing (like the mammoth nine-bedroom, built this year, that's selling for $19.8 million) is enough to skew the median price skyward.”<br><br />
[http://realestate.yahoo.com/promo/americas-most-expensive-zip-codes-2010.html America’s Most Expensive ZIP Codes 2010”], <i>Yahoo! Real Estate</i>, September 27, 2010</blockquote><br />
Note that someone at Forbes must have spotted the potential error in the last 8 words. While the original sentence remains on the Yahoo website, the sentence now ends “may not adequately represent how everyone in the area lives” at the Forbes website[http://www.forbes.com/2010/09/27/most-expensive-zip-codes-2010-lifestyle-real-estate-zip-codes-10-intro.html].<br><br />
<br />
Submitted by Margaret Cibes at the suggestion of Cris Wellington<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to the Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department."<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 120 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Sampling saliva==<br />
[http://www.thenation.com/article/154596/freshmen-specimen “Freshmen Specimen”]<br><br />
by Patricia J. Williams, <i>The Nation</i>, September 27, 2010<br> <br />
<br />
In this column, law professor Williams describes reactions to the University of California’s Berkeley project [http://onthesamepage.berkeley.edu/ “Bring Your Genes to Cal”], in which 5500 incoming freshmen were asked to provide saliva samples for the purpose of “bring[ing] the student body together in the same manner that reading To Kill a Mockingbird might have in the past.” More than 700 students submitted their samples to an uncertified Berkeley lab, and the samples were analyzed for “susceptibility to alcoholism, lactose intolerance and relative metabolism of folic acid.”<br><br />
<br />
<blockquote>[T]he California Department of Public Health barred the university from dispensing individual profiles on the grounds that genetic analysis is correlative only and is neither necessarily predictive nor diagnostic at this point. A collective comparison of the class's genetic data was permitted, however, and circulated in "anonymized" form at orientation.</blockquote><br />
<br />
Some ethical issues that have been raised include:<br><br />
(a) privacy, despite the “anonymizing” of results;<br><br />
(b) ownership of the data with respect to commercialization, patentability, remuneration, etc.;<br><br />
(c) promotion of the concept that a genetic correlation is a “100 percent infallible guarantee” of anything;<br><br />
(d) motive with respect to promoting sales of swab kits.<br><br />
<br />
The article refers to a Stanford University medical school class “spit party” and to a University of Minnesota [http://www.peds.umn.edu/gopherkids/ "Gopher Kids"] program (free gifts for saliva swabs at a state fair).<br />
<br />
Readers might be interested in a paper from ETC Group, a Canadian-based international organization, [http://www.etcgroup.org/upload/publication/675/02/genomixspitkits_03march08.pdf "Direct-to-Consumer DNA Testing and the Myth of Personalized Medicine: Spit Kits, SNP Chips and Human Genomics"]. Or they might want to google "spit party" to see how widespread these activities are.<br />
<br />
===Discussion===<br />
<br />
1. Explain what the Public Health Department meant by the clause "genetic analysis is correlative only." <br />
<br />
2. Comment on the following statement in the article: “The university advertises participation as altruistic, a contribution to public health and human knowledge.”<br><br />
<br />
3. The author of the article refers to the process of collecting saliva samples as a “commodity exchange.” Do you agree with the author?<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11272Chance News 672010-10-07T14:54:17Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
An article describes two brands of athletic wear that are claimed to optimize performance via embedded holograms (Power Balance) and water-soluble titanium (Phiten).<br />
<blockquote>“A lot of these products are a sort of merchandized superstition. …. [A French surfer states,] ‘But if wearing the thing makes you think you feel or perform better, who cares?’”<br><br />
[http://www.time.com/time/magazine/article/0,9171,2021057,00.html “Wrist Watch”], <i>TIME</i>, October 4, 2010</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>”A scant 1,391 people live in 91008 ZIP code, and only 12 homes are currently on the market. So a single high-priced listing (like the mammoth nine-bedroom, built this year, that's selling for $19.8 million) is enough to skew the median price skyward.”<br><br />
[http://realestate.yahoo.com/promo/americas-most-expensive-zip-codes-2010.html America’s Most Expensive ZIP Codes 2010”], <i>Yahoo! Real Estate</i>, September 27, 2010</blockquote><br />
Note that someone at Forbes must have spotted the potential error in the last 8 words. While the original sentence remains on the Yahoo website, the sentence now ends “may not adequately represent how everyone in the area lives” at the Forbes website[http://www.forbes.com/2010/09/27/most-expensive-zip-codes-2010-lifestyle-real-estate-zip-codes-10-intro.html].<br><br />
<br />
Submitted by Margaret Cibes at the suggestion of Cris Wellington<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department."<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 120 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Sampling saliva==<br />
[http://www.thenation.com/article/154596/freshmen-specimen “Freshmen Specimen”]<br><br />
by Patricia J. Williams, <i>The Nation</i>, September 27, 2010<br> <br />
<br />
In this column, law professor Williams describes reactions to the University of California’s Berkeley project [http://onthesamepage.berkeley.edu/ “Bring Your Genes to Cal”], in which 5500 incoming freshmen were asked to provide saliva samples for the purpose of “bring[ing] the student body together in the same manner that reading To Kill a Mockingbird might have in the past.” More than 700 students submitted their samples to an uncertified Berkeley lab, and the samples were analyzed for “susceptibility to alcoholism, lactose intolerance and relative metabolism of folic acid.”<br><br />
<br />
<blockquote>[T]he California Department of Public Health barred the university from dispensing individual profiles on the grounds that genetic analysis is correlative only and is neither necessarily predictive nor diagnostic at this point. A collective comparison of the class's genetic data was permitted, however, and circulated in "anonymized" form at orientation.</blockquote><br />
<br />
Some ethical issues that have been raised include:<br><br />
(a) privacy, despite the “anonymizing” of results;<br><br />
(b) ownership of the data with respect to commercialization, patentability, remuneration, etc.;<br><br />
(c) promotion of the concept that a genetic correlation is a “100 percent infallible guarantee” of anything;<br><br />
(d) motive with respect to promoting sales of swab kits.<br><br />
<br />
The article refers to a Stanford University medical school class “spit party” and to a University of Minnesota [http://www.peds.umn.edu/gopherkids/ "Gopher Kids"] program (free gifts for saliva swabs at a state fair).<br />
<br />
Readers might be interested in a paper from ETC Group, a Canadian-based international organization, [http://www.etcgroup.org/upload/publication/675/02/genomixspitkits_03march08.pdf "Direct-to-Consumer DNA Testing and the Myth of Personalized Medicine: Spit Kits, SNP Chips and Human Genomics"]. Or they might want to google "spit party" to see how widespread these activities are.<br />
<br />
===Discussion===<br />
<br />
1. Explain what the Public Health Department meant by the clause "genetic analysis is correlative only." <br />
<br />
2. Comment on the following statement in the article: “The university advertises participation as altruistic, a contribution to public health and human knowledge.”<br><br />
<br />
3. The author of the article refers to the process of collecting saliva samples as a “commodity exchange.” Do you agree with the author?<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11260Chance News 672010-10-04T23:44:54Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department."<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 109 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11259Chance News 672010-10-04T13:46:01Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department.<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, are amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 109 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11253Chance News 672010-10-02T14:35:17Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review excerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department.<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, and amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 109 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_67&diff=11252Chance News 672010-10-02T02:50:53Z<p>PaulAlper: /* Proofiness */</p>
<hr />
<div>==Quotations==<br />
==Forsooth==<br />
<br />
==More fuel to feed the fiery controversy over mammograms==<br />
<br />
[http://www.nytimes.com/2010/09/30/health/research/30mammogram.html Mammogram Benefit Seen for Women in Their 40s], Gina Kolata, The New York Times, September 29, 2010.<br />
<br />
One of the most contentious debates in medicine is whether mammograms are beneficial to women between 40 and 50 years old. Earlier commentaries about this controversy appear in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Chance News 8], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_12#Screening Chance News 12], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Chance News 14], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_47#Bayes_theorem_in_the_news Chance News 47], [http://www.causeweb.org/wiki/chance/index.php/Chance_News_58#Mammogram_Math Chance News 58], and [http://www.causeweb.org/wiki/chance/index.php/Chance_News_59#Ill_health_news Chance News 59].<br />
<br />
The first sentence in the latest article about mammography makes a bold claim...<br />
<br />
<blockquote>Researchers reported Wednesday that mammograms can cut the breast cancer death rate by 26 percent for women in their 40s.</blockquote><br />
<br />
...and the second sentence contradicts this claim.<br />
<br />
<blockquote>But their results were greeted with skepticism by some experts who say they may have overestimated the benefit.</blockquote><br />
<br />
The data set on which these bold claims were based is quite good.<br />
<br />
<blockquote>The new study took advantage of circumstances in Sweden, where since 1986 some counties have offered mammograms to women in their 40s and others have not, according to the lead author, Hakan Jonsson, professor of cancer epidemiology at Umea University in Sweden. The researchers compared breast cancer deaths in women who had a breast cancer diagnosis in counties that had screening with deaths in counties that did not. The rate was 26 percent lower in counties with screening.</blockquote><br />
<br />
Why the skepticism?<br />
<br />
<blockquote>One problem, said Dr. Peter C. Gotzsche of the Nordic Cochrane Center in Copenhagen, a nonprofit group that reviews health care research, is that the investigators counted the number of women who received a diagnosis of breast cancer and also died of it. They did not compare the broader breast cancer death rates in the counties.</blockquote><br />
<br />
A prominent statistician, Donald Berry, is also quoted in this article.<br />
<br />
===Questions===<br />
<br />
1. The research design in the current study was not randomized. Is this an issue?<br />
<br />
2. What are the barriers to conducting a randomized trial for mammography?<br />
<br />
==Proofiness==<br />
<br />
Charles Seife is a marvelous writer of serious, interesting topics for the lay reader:<br />
<ul><br />
<li>''Zero: The Biography of a Dangerous Idea'', 2000<br />
<li>''Alpha & Omega: The Search for the Beginning and End of the Universe'', 2004<br />
<li>''Decoding The Universe'', 2007<br />
<li>''Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking'', 2008<br />
</ul><br />
His latest book, ''Proofiness: The Dark Arts of Mathematical Deception'', 2010, makes for especially good reading for students and teachers of statistics. The following web sites all comment on the book: The New York Times has a [http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html?_r=1&ref=bookreviews review] and an [http://www.nytimes.com/2010/09/16/books/excerpt-proofiness.html?ref=review exerpt]; NPR ran a story, [http://www.npr.org/templates/story/story.php?storyId=129972868 Lies, Damned Lies, And 'Proofiness']; additional reviews appeared<br />
in [http://www.nyjournalofbooks.com/2010/09/proofiness-dark-arts-of-mathematical.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NewYorkJournalOfBooks+(NEW+YORK+JOURNAL+OF+BOOKS) New York Journal of Books] and [http://www.politicsdaily.com/2010/08/01/proofiness-using-numbers-to-fool-people-and-shape-political-deb/ Politics Daily].<br />
<br />
The reviews are entirely favorable, but don’t quite do justice to his presentation, so readers of Chance News are encouraged to read the book as well as the above commentaries.<br />
<br />
Seife defines proofiness as “the art of using bogus mathematical arguments to prove something that you know in your heart is true — even when it’s not.” However, he never makes the connection to [http://www.innumeracy.com/ Innumeracy] <br />
<blockquote><br />
A term meant to convey a person's inability to make sense of the numbers that run their lives. Innumeracy was coined by cognitive scientist Douglas R Hofstadter in one of his Metamagical Thema columns for Scientific American in the early nineteen eighties. Later that decade mathematician John Allen Paulos published the book Innumeracy. In it he includes the notion of chance as well to that of numbers.<br />
</blockquote><br />
Seife also does not refer to Stephen Colbert’s even more famous neologism, [http://en.wikipedia.org/wiki/Truthiness truthiness] which<br />
<br />
<blockquote><br />
is a "truth" that a person claims to know intuitively "from the gut" without regard to evidence, logic, intellectual examination, or facts.<br />
</blockquote><br />
<br />
Colbert himself put truthiness this way:<br />
"We're not talking about truth, we're talking about something that seems like truth – the truth we want to exist."<br />
<br />
Seife begins his Introduction with the famous quotation of Senator Joseph McCarthy on February 9, 1950:<br />
<br />
<blockquote><br />
"I have here in my hand a list of 205--a list of names that were made known to Secretary of State as being members of the Communist party and who nevertheless are still working and shaping policy in the State Department.<br />
<blockquote><br />
</blockquote><br />
The 205 later became 57 and then 81. “It really didn’t matter whether the list had 205 or 57 or 81 names. The very fact that McCarthy had attached a number to his accusations imbued them with an aura of truth.” This “outrageous falsehood was given the appearance of absolute fact.”<br />
</blockquote><br />
<br />
Seife attempts to categorize the types of proofiness:<br />
<br />
A. Potemkin numbers--numerical facades that look like real numbers such as crowd estimates or the number of communists in the State Department.<br><br />
B. Disestimation, another neologism--“the act of taking a number too literally, understating or ignoring the uncertainties that surround it.”<br><br />
C. Fruit packing--“it’s not the individual numbers that are false; it is the presentation of the data that creates the proofiness.”<br><br />
D. Cherry picking--a form of fruit packing in which there is a “careful selection of data, choosing those that support the argument you wish to make while underplaying or ignoring data that undermine it.”<br><br />
E. Apples to oranges comparison--another form of fruit packing, for example, comparing dollar amounts without taking into account inflation.<br><br />
F. Apple polishing--another form of fruit packing, for example, deceptive graphs where the origin is missing; or, algebraically, misuse of mean and median.<br><br />
G. Causuistry, another neologism and a pun on the word casuistry--“a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn’t any such linkage.”<br><br />
H. Randumbness, another neologism--“insisting that there is order where there is only chaos” or, “creating a pattern where there is none to see.”<br><br />
I. Regression to the moon--for example, extrapolating instead of interpolating regression results.<br><br />
<br />
None of these categories are new to teachers of statistics but his examples of the above forms of proofiness are detailed and when not frightening, and amusing; these examples include: the O.J. Simpson trial; the Franken-Coleman Minnesota Senate election and Bush vs. Gore in 2000 (he terms them “electile dysfunctions”); nuclear testing; risk analysis; the space program; the Vietnam war; and, determination of the perfect butt (page 66 contains the formula for callipygianness--a word which is '''not''' a neologism). He is particularly incisive when he contrasts systematic error when it overwhelms and confuses the notion of error due to sampling, and thus, invalidating the so-called margin of error in polling. <br />
<br />
===Discussion===<br />
<br />
1. If it is so obvious today that McCarthy was fabricating the numbers--in the parlance of today, he was fact-free--why was he so successful so long in the 1950s? And why did his allegations and point of view live on well after his death in 1957?<br />
<br />
2. Seife devotes a great deal of time to convince the reader that the U.S. census would be more accurate if it did not attempt to count everyone but rather did statistical sampling and avoid many of the systematic errors. Why would this be true? Why did the U.S. Supreme Court deem otherwise?<br />
<br />
3. Some of his strongest criticism is directed at journalists and polling organizations. The chapter entitled, “Poll Cats.” On page 109 he says, “Internet polls have no basis in reality whatsoever.” Why? “Yet, CNN.com has an Internet poll on its front page every day.” Again, why? Non Internet polls do not come off much better due to flagrant non-statistical faults.<br />
<br />
4. With regard to the O.J. Simpson murder trial, Seife paraphrases one of Simpson's defense attorneys claim that “only one in a thousand wife-beaters winds up murdering his spouse. One in a thousand! Such a small probability means that O.J. Simpson almost certainly isn’t the murderer, right? “ Use Bayes theorem along with reasonable numbers about the number of wives being murdered to indicate that Simpson’s probability of being the culprit is much higher.<br />
<br />
5. Regression to the moon also refers to totally nonsensical use of regression. A more detailed look (page 66) at callipygianness reveals<br />
<center><br />
Callipygianness = (S + C) x (B + F) / (T - V) ,<br />
</center><br />
where S is shape, C is circularity, B is bounciness, F is firmness, T is texture, and V is waist-to-hip ratio. Seife found this regression result, not surprisingly, on <br />
[http://www.foxnews.com/story/0,2933,191622,00.html Fox News] and the reporter was from another Murdoch enterprise, The New York Post. Why does Seife find this regression result so ridiculous? On the same page, there is a regression result for “Misery” which depends upon weather, debt, motivation, “the need to take action,” and some other variables. “[I]t proved --scientifically--that the most miserable day of the year [2005] was January 24.” The regression result for “Happiness” appears on the preceding page. Why does Seife claim that these three are examples of Potemkin numbers?<br />
<br />
6. To return to McCarthy’s proofiness, his original speech about the 205 communists in the State Department was made in Wheeling, West Virginia to the Republican Women’s Club and made no waves whatsoever for days. Seife does not mention this, but only after the New York Times and the Washington Post publicized the speech did it ignite his fame. Contrast that time lag with today’s instant communication.<br />
<br />
7. Seife on page 226 repeats a famous adage of the journalism world: “If your mother says she loves you, check it out.” He then looks at the Pentagon’s weekly body counts and monthly hamlet evaluations during the Vietnam War. By page 228 he describes an auto-industry market research report which shows that driving a Hummer H3 is “better for the environment than driving the energy-efficient Toyota Prius hybrid.” Why did he juxtapose these two examples?<br />
<br />
8. The last paragraph of the book is: “Mathematical sophistication is the only antidote to proofiness and our degree of knowledge will determine whether we succumb to proofiness or fight against it. It’s more than mere rhetoric; our democracy may well rise or fall by the numbers.” Why might his “antidote” be insufficient?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_66&diff=11188Chance News 662010-09-16T02:22:25Z<p>PaulAlper: /* Data matters */</p>
<hr />
<div>==Quotations==<br />
<blockquote>&quot;It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.&quot; <br> --Mark Twain</blockquote><br />
<br />
Quoted by Richard H. Thaler in [http://www.nytimes.com/2010/08/22/business/economy/22view.html?_r=1&scp=9&sq=estimate&st=cse The overconfidence problem in forecasting], ''New York Times'', 21 August 2010. <br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth==<br />
The following Forsooth is from the August 23, 2010 RRS News.<br />
<br />
An [http://jnci.oxfordjournals.org/cgi/content/full/101/23/NP editorial] was published in the ''Journal of the National Cancer Institute'' (Volume 101, no 23, 2 December 2009). It announced some online resources for journalists, including a [http://www.oxfordjournals.org/our_journals/jnc/resource/statistics%20glossary.pdf statistics glossary], which gave the following definitions:<br />
<br />
<UL><br />
<li>'''P value.''' &nbsp;Probability that an observed effect size is<br />
due to chance alone.<br />
<p>if p &ge; 0.05, we say 'due to chance', 'not statistically significant'</p><br />
<p>if p < 05, we say 'not due to chance', 'statistically significant'</p><br />
<br />
<li>'''Confidence interval''' (95% CI)<br />
<br />
<p>Because the observed value is only an estimate of the truth, we know it has a 'margin of error'.</p><br />
<p>The range of plausible values around the observed value that will contain the truth 95% of the time.</p><br />
</UL> <br />
The journal subsequently (vol. 102, no. 11, 2 June 2010) published a letter commenting on the editorial and the statistics glossary. The authors of the original editorial replied as follows:<br />
<blockquote><br />
<p>Dr Lash correctly points out that the descriptions of p values and 95% confidence intervals do not meet the<br />
formal frequentist statistical definitions.</p><br />
<br />
<p>[…] We were not convinced that working journalists would find these definitions<br />
user-friendly, so we sacrificed precision for utility.</p><br />
</blockquote><br />
<br />
Submitted by Laurie Snell<br />
<br />
==Risk reduction==<br />
[http://www.reuters.com/article/idUSTRE67C2GE20100813 Burger and a statin to go? Or hold that, please?] <br><br />
by Kate Kelland and Genevra Pittman, ''Reuters'', 13 August 2010<br />
<br />
Dr. Darrel Francis is the leader of "a study published in the American Journal of Cardiology, [in which] scientists from the National Heart and Lung Institute at Imperial College London calculated that the reduction in heart disease risk offered by a statin could offset the increase in risk from eating a cheeseburger and a milkshake."<br />
<br />
Further, "When people engage in risky behaviors like driving or smoking, they're encouraged to take measures that minimize their risk, like wearing a seatbelt or choosing cigarettes with filters. Taking a statin is a rational way of lowering some of the risks of eating a fatty meal."<br />
<br />
'''Discussion'''<br />
<br />
1. Obviously, the above comments and analogies are subject for debate. Defend and criticize the comparisons made.<br />
<br />
2. Risk analysis is very much in the domain of statistics. How would you estimate the risk of driving, smoking, eating a cheeseburger or taking a statin? Read the article in the American Journal of Cardiology to see how Francis and his co-authors estimated risk.<br />
<br />
3. [http://en.wikipedia.org/wiki/Pascal%27s_Wager Pascal’s Wager] is famous in religion, philosophy and statistics; his wager is the ultimate in risk analysis. <br />
<blockquote><br />
Historically, Pascal's Wager was groundbreaking as it had charted new territory in probability theory, was one of the first attempts to make use of the concept of infinity, [and] marked the first formal use of decision theory.<br />
</blockquote><br />
The wager is renowned for discussing the risk of not believing in God, presumably the Christian concept of God.<br />
<blockquote><br />
<br />
[A] person should [http://en.wikipedia.org/wiki/Gambling wager]<br />
as though God exists, because living life accordingly has everything to gain, and nothing to lose.<br />
</blockquote><br />
Read the Wikipedia article and discuss the risk tables put forth.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Teaching with infographics==<br />
[http://learning.blogs.nytimes.com/2010/08/23/teaching-with-infographics-places-to-start/ Teaching with infographics: Places to start]<br><br />
by Katherine Schulten, ''New York Times'', The Learning Network blog, 23 August 2010<br />
<br />
Each day of this week, the blog will present commentary on some aspect of infographics. Starting with discussion of what infographics are, the series proceeds through applications ranging from sciences and social sciences to the fine arts. Each category will feature examples that have appeared in the ''Times''. The link above for the first day contains an index to the whole series. There is a wealth of material to browse here.<br />
<br />
Submitted by Bill Peterson<br />
<br />
==Subverting the Data Safety Monitoring Board==<br />
<br />
[http://www.nejm.org/doi/full/10.1056/NEJMe1007445 Don't Mess with the DSMB] Jeffrey M. Drazen and Alastair J.J. Wood. N Engl J Med 2010; 363:477-478, July 29, 2010.<br />
<br />
The Data Safety Monitoring Board (DSMB) is supposed to be an independent group charged with interim review of data from a clinical trial to decide whether to stop a study early because of evidence that continuation of the trial would be unethical. Trials are commonly halted early because of sufficient evidence that a new drug is clearly superior/inferior to the comparison drug, or because of serious concerns about safety.<br />
<br />
The independent function of a DSMB is vital.<br />
<br />
<blockquote>Since the DSMB (data and safety monitoring board) is charged with ensuring that clinical equipoise is maintained as trial data are accrued, it is considered very bad, even self-destructive, behavior for people who are involved with the study to interact with DSMB members on trial-related issues. Traditionally, there has been a wall between investigators, sponsors, and the DSMB. This wall prevents preliminary findings from leaking out in ways that would prejudice the trial. For example, if it was known that the DSMB was examining a marginal increase in cardiovascular risk in a trial, then trial investigators might bias future recruitment by excluding patients at risk for such events.</blockquote><br />
<br />
In the real world, though, problems with the DSMB occur. In one case, a drug company bypassed the DSMB and conducted an in-house examination of data in a trial and quickly published the data to counter a recently published meta-analysis that suggested safety issues associated with that company's drug. Why is this a problem?<br />
<br />
<blockquote>The DSMB should have been informed of our May 2007 article and checked the trial data to be sure that patients receiving rosiglitazone in the RECORD trial were not having adverse events at an unacceptable rate. If clinical equipoise was still in play, the trial should have been allowed to continue undisturbed (i.e., without publication of the RECORD interim analysis), without public comment from the DSMB, without communication with investigators, and without disturbing the integrity of the trial. On the other hand, if in the opinion of the DSMB equipoise no longer existed, then the trial should have been terminated — that is the way it is supposed to work. The DSMB protects the participants in a trial.</blockquote><br />
<br />
This editorial described a second trial where interim data that should have been blinded from everyone except the DSMB became publicly known. A detailed description of this trial can be found [http://www.nejm.org/doi/full/10.1056/NEJMsr0900910 in an earlier NEJM article].<br />
<br />
Another concern about revelation of data in a DSMB involves the potential for insider trading. There is a nice description of the problems that disclosure can have in [http://seattletimes.nwsource.com/html/businesstechnology/drugsecrets1.html this Seattle Times article from 2005].<br />
<br />
===Questions===<br />
<br />
1. Some DSMBs analyze data that is blinded by coding the two arms of the study with generic letters like A and B. With generic letters, though, it still may be possible to guess which group is which. How?<br />
<br />
2. There are also examples where the DSMB is presented only with aggregate data across both arms of the study. What types of safety issues could be analyzed with only aggregate data? What types of safety issues would be impossible to conduct with only aggregate data?<br />
<br />
3. If the rules for stopping a study are specified in detail prior to data collection, would a DSMB still be needed?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Think the answers clear? Look again==<br />
<br />
[http://www.nytimes.com/2010/08/31/science/31profile.html?ref==%20scienceNews%20New%20York%20Times%20 The New York Times Science]<br><br />
by Katie Hafner<br><br />
August 30, 2010<br />
<br />
Here we read:<br />
<br />
Presidential elections can be fatal.<br />
<br />
(1) Win an Academy Award and you’re likely to live longer than had you been a runner-up.<br />
<br />
(2) Interview for medical school on a rainy day, and your chances of being selected could fall.. <br />
<br />
Win an Academy Award and you’re likely to live longer than had you been a runner-up.<br />
<br />
Interview for medical school on a rainy day, and your chances of being selected could fall.<br />
<br />
Such are some of the surprising findings of Dr. Donald A. Redelmeier, a physician-researcher and perhaps the leading debunker of preconceived notions in the medical world.<br />
<br />
Readers of chance news will recall that it was the claim that Osker winners live longer that was debunked.<br />
<br />
See these<br><br />
<br />
[http://www.causeweb.org/wiki/chance/index.php/Oscar_winners_do_not_live_longer Oscor winners do not live longer]<br />
<br />
[http://www.mcgill.ca/newsroom/news/item/?item_id=21645 McGill researchers debunk Oscar-winner 'longevity bonus']<br />
<br />
[http://www.annals.org/content/145/5/392.2.full Reanalysis of Survival of Oscar Winners]<br />
<br />
Submited by Laurie Snell<br />
<br />
==Is the United States a religious outlier?==<br />
<br />
[http://www.nytimes.com/2010/09/04/opinion/04blow.html Religious outlier] by Charles Blow, The New York Times, September 4, 2010.<br />
<br />
The following image was published on the New York Times website.<br />
<br />
http://graphics8.nytimes.com/images/2010/09/04/opinion/0904OPEDBLOW_600sub.jpg<br />
<br />
The author, Charles Blow, is the visual OpEd columnist for the New York Times. His comments about the graph are rather brief.<br />
<br />
<blockquote>With all of the consternation about religion in this country, it’s sometimes easy to lose sight of just how anomalous our religiosity is in the world. A Gallup report issued on Tuesday underscored just how out of line we are. Gallup surveyed people in more than 100 countries in 2009 and found that religiosity was highly correlated to poverty. Richer countries in general are less religious. But that doesn’t hold true for the United States.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Does the United States look like an outlier to you? Are there any other outliers on this graph?<br />
<br />
2. Why would there be a relationship between GDP and percentage of people who call themselves religious? Does a higher GDP cause lower religiosity? Does a lower religiosity cause a higher GDP? What sort of data could you collect that might help answer this question?<br />
<br />
3. Do you like how Mr. Blow presented this data? What would you change, if anything, in this graph?<br />
<br />
Submitted by Steve Simon<br />
<br />
===Additional Discussion===<br />
Notice how many dimensions are included in addition to the axes (percentage who say religion is important and G.D.P. per capita). The Gallup poll from which the graph came can be found [http://www.gallup.com/poll/142727/religiosity-highest-world-poorest-nations.aspx here]. Gallup says: <br />
<blockquote><br />
Results are based on telephone and face-to-face interviews conducted in 2009 with approximately 1,000 adults in each country. For results based on the total sample of national adults, one can say with 95% confidence that the maximum margin of sampling error ranges from ±5.3 percentage points in Lithuania to ±2.6 percentage points in India. In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.<br />
</blockquote> <br />
What might be "practical difficulties in conducting surveys"? "wording difficulties"? What effect might these have on the findings?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Perfect Handshake formula==<br />
[http://www.newspress.co.uk/public/ViewPressRelease.aspx?pr=23313 “Scientists Create Formula for Perfect Handshake”]<br><br />
<i>Newspress</i>, July 15, 2010<br><br />
<br />
A University of Manchester psychologist has developed a formula for the Perfect Handshake. The formula was devised as part of a project for UK Chevrolet, who wanted a handshake training guide to be used by its sales force in promoting a new warranty plan.<br><br />
<br />
An edited version of the formula is given by: <br />
<blockquote>PH^2 = (e^2 + ve^2)(d^2) + (cg + dr)^2 + pi(4s^2)(4p^2)]^2 + (vi + t + te)^2 + [(4c^2)(4du^2]^2</blockquote><br />
<br />
where the following variables are measured on a scale of 1 to 5 for low to high traits, respectively:<br><br />
<br />
(a) optimum score 5: e = eye contact; ve = verbal greeting; d = Duchenne smile; cg = completeness of grip<br><br />
(b) optimum score 4: dr = dryness of hand<br> <br />
(c) optimum score 3: s = strength; p = position of hand; vi = vigor; t = temperature of hands; te = texture of hands; c = control; du = duration. <br><br />
<br />
The article gives more details about the rating standards, as well as a phone number and email address with which to obtain a copy of the handshake training guide.<br><br />
<br />
<b>Discussion</b><br><br />
1. Interpret the phrase "optimum score" for each variable.<br><br />
2. Find the minimum, optimum, and maximum Perfect Handshake scores.<br><br />
3. Comment on the range of possible scores.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Wondering about NFL IQs?==<br />
[http://en.wikipedia.org/wiki/Wonderlic_Test “Wonderlic Test”]<br><br />
Wikipedia, retrieved September 12, 2010<br><br />
<br />
The Wonderlic[http://www.wonderlic.com/] Personnel Test is a 12-minute, 50-question multiple-choice test of English and math, which is used to help employers evaluate the general aptitude of job candidates in many occupations.<br><br />
<br />
A candidate’s score is the total number of correct answers, with a score of 20 indicating average intelligence. For NFL pre-draft candidates, average scores range from 16 (halfback) to 26 (offensive tackle).<br><br />
<br />
Pat NcInally, of Harvard, holds the record for a perfect score of 50. However, Dan Marino and Vince Young both scored 16 on the test. (See [http://espn.go.com/page2/s/closer/020228test.html “So, how do you score?”] for sample questions from a Wonderlic 2007 test.)<br><br />
<br />
Business professor McDonald Mirabile is said to have compiled Wonderlic scores for 241 NFL quarterbacks in 2010, and found a mean score of 25.22 and a standard deviation of 7.46. Assuming that the standard deviation of any subgroup will not differ significantly from that of the population as a whole, the Wikipedia article suggests an equation relating a Wonderlic score to a standard IQ test score:<br />
<blockquote> IQ = 100 + [(W − 20) / 7.46] * 15.</blockquote> <br />
<i>Note</i>: Professor Mirabile’s 2005 study[http://www.thesportjournal.org/article/intelligence-and-football-testing-differentials-collegiate-quarterback-passing-performance-a] of 84 drafted and signed quarterbacks from 1989 to 2004 showed “no statistically significant relationship between intelligence and collegiate passing performance.”<br><br />
<br />
<b>Discussion</b><br><br />
1. Explain the role of each number, and numerical expression, in the equation relating a Wonderlic score to a standard IQ test score.<br><br />
2. An SAT Reasoning Test (called "Scholastic Aptitude Test" pre-2005) score is scaled to a mean of 500 and a standard deviation of 100. Suggest an analogous equation relating a Wonderlic score to an SAT Reasoning score.<br><br />
3. While any pair of these scores <i>can</i> be related to each other via an equation, do you believe that they <i>should</i> be, <i>i.e.</i>, that such relationships would be meaningful? What else would you need to know in order to decide?<br><br />
4. Suppose that the Wonderlic test is not related to passing performance at all, at least for quarterbacks. What other aspect(s) of good quarterbacking, if any, might it measure?<br> <br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Too much data on risks of BPA==<br />
<br />
[http://www.nytimes.com/2010/09/07/science/07bpa.html In Feast of Data on BPA Plastic, No Final Answer]. Denise Grady, The new York Times, September 6, 2010.<br />
<br />
The more research there is in an area, the greater the chances of reaching a consensus. That's seems intuitive enough, but for the case of BPA, more data does not seem to help resolve this contentious area.<br />
<br />
<blockquote>The research has been going on for more than 10 years. Studies number in the hundreds. Millions of dollars have been spent. But government health officials still cannot decide whether the chemical bisphenol-A, or BPA, a component of some plastics, is safe.</blockquote><br />
<br />
There are plenty of examples where one research study contradicts another, but usually scientists agree that one of the studies trumps the results of the other one because of superior research design. This does not appear to be the case with BPA.<br />
<br />
<blockquote>The mountains of data produced so far show conflicting results as to whether BPA is dangerous, in part because different laboratories have studied the chemical in different ways. Animal strains, doses, methods of exposure and the results being measured — as crude as body weight or as delicate as gene expression in the brain — have all varied, making it difficult or impossible to reconcile the findings. In science, no experiment is taken seriously unless other researchers can reproduce it, and difficulties in matching BPA studies have led to fireworks. </blockquote><br />
<br />
Scientists are arguing over which set of studies to believe.<br />
<br />
<blockquote>Most of the evidence against BPA comes from studies that find harmful effects in rats and mice at low doses comparable to the levels to which people are exposed. Sometimes the results seem downright weird, indicating that low doses could be worse than higher ones. There is sharp disagreement among scientists about how to interpret some research. The disputes arise in part because scientists from different disciplines — endocrinologists versus toxicologists, academic researchers versus those at regulatory agencies — do research in different ways that can make findings hard to reconcile. </blockquote><br />
<br />
There are some patterns to the findings.<br />
<br />
<blockquote>She and other scientists said studies by university labs tended to find low-dose effects, and studies by government regulatory agencies and industry tended not to find them. The split occurs in part because the studies are done differently. Universities, Dr. Birnbaum said, “have moved rapidly ahead with advances in science,” while regulators have used “older methods.” Some researchers consider the regulatory studies more reliable because they generally use much larger numbers of animals and adhere to formal guidelines called “good laboratory practices,” but Dr. Birnbaum described those practices as “good record-keeping” and said, “That doesn’t mean the right questions were being asked.” The low-dose studies are newer and have raised safety issues that need to be resolved, she said. Last year, a scientific group called the Endocrine Society issued a 34-page report expressing serious concerns about endocrine-disrupting compounds, including BPA, dioxins, PCBs, DDT, the plasticizers known as phthalates and DES. </blockquote><br />
<br />
===Questions===<br />
<br />
1. Are there other areas of science where research studies fail to reach the same conclusion.<br />
<br />
2. Is the inability to use randomized trials in this area a possible explanation for why one set of studies is not considered to be definitive? What are some other possible explanations?<br />
<br />
3. When a study fails to show a dose-response relationship, greater effect at a higher dose than at a lower dose, that is considered a serious problem. Is there a possible explanation for the lack of dose-response in these studies?<br />
<br />
Submitted by Steve Simon<br />
<br />
==All the news that the data tell us is fit to print==<br />
<br />
[http://www.nytimes.com/2010/09/06/business/media/06track.html Some Newspapers, Tracking Readers Online, Shift Coverage], Jeremy W. Peters, The New York Times, September 5, 2010.<br />
<br />
Newspapers are not like other businesses.<br />
<br />
<blockquote>In most businesses, not knowing how well a particular product is performing would be almost unthinkable. But newspapers have always been a peculiar business, one that has stubbornly, proudly clung to a sense that focusing too much on the bottom line can lead nowhere good.</blockquote><br />
<br />
But that may be changing.<br />
<br />
<blockquote>Now, because of technology that can pinpoint what people online are viewing and commenting on, how much time they spend with an article and even how much money an article makes in advertising revenue, newspapers can make more scientific decisions about allocating their ever scarcer resources.</blockquote><br />
<br />
This is quite different from the readers polls about which comic strips to keep or delete. The article goes on to describe how major newspapers like the Wall Street Journal and the Washington Post use web traffic data to make decisions about how and what to cover. There are dissenting voices, and the New York Times, where this article originated, says that they do not make decisions about coverage based on statistics.<br />
<br />
Submitted by Steve Simon<br />
<br />
==Data matters==<br />
[http://en.wikipedia.org/wiki/Evidence-based_medicine Evidence-based medicine] “or Evidence-based practice (EBP) aims to apply the best available evidence gained from the scientific method to clinical decision making.” EBP can be viewed as a technique for discerning what is true versus what is plausibly valid. Often, careful research protocols indicate such items as vitamin E, beta carotene, fiber, massive screening for cancer, etc., fail to live up to expectations even though we intuitively feel they must be beneficial. <br />
<br />
A recent article [http://well.blogs.nytimes.com/2010/09/01/phys-ed-does-stretching-before-running-prevent-injuries/?scp=1&sq=gretchen%20reynolds&st=cse Phys Ed: Does Stretching Before Running Prevent Injuries?] (New York Times, 1 September 2010) cites another case where EBP counters intuition and plausibility. We all “know” that stretching before running is beneficial. Yet, when the 1400 runners varying in age from “13 to past 60” were randomly assigned to (static) stretching and to not stretching:<br />
<br />
<blockquote><br />
About 16 percent of the group that didn’t stretch were hobbled badly enough to miss training for at least three days (the researchers’ definition of a running injury), while about 16 percent of the group that did stretch were laid up for the same amount of time.<br />
</blockquote><br />
<br />
However, in order to overthrow our intuition in favor of what EBP is telling us, we have to believe the data is honestly presented. Such belief can be naïve especially when money plays a vital role. The case of [http://topics.nytimes.com/topics/reference/timestopics/people/k/timothy_r_kuklo/index.html Timothy Kuklo] has appeared several times in Chance News (see entries in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II CN 50], <br />
[http://www.causeweb.org/wiki/chance//index.php/Chance_News_49#Infuse_and_Kuklo_II CN 49], and [http://www.causeweb.org/wiki/chance//index.php/Chance_News_48#Infuse_and_Kuklo CN 48]). Other conflicts of interest and failures to state such conflicts has been an ongoing embarrassment for medical journals. See [http://www.nytimes.com/2010/09/14/business/14devices.html?partner=rss&emc=rss Medical Industry Ties Often Undisclosed in Journals] (New York Times, 13 September 2010) for recent egregious instances.<br />
<br />
Unfortunately, fraudulent data also arises in areas outside of medicine and the academic world. Especially if data is taken over time, the urge to fake it in subsequent periods is overwhelming as indicated by Sir Walter Scott’s famous quotation, ''Oh what a tangled web we weave when first we practice to deceive.''<br />
The depressing story of NYPD’s continuing corruption and increased data faking may be found in [http://www.villagevoice.com/2010-05-04/news/the-nypd-tapes-inside-bed-stuy-s-81st-precinct/ The Village Voice]:<br />
<br />
<blockquote><br />
As a result, the tapes show, the rank-and-file NYPD street cop experiences enormous pressure in a strange catch-22: He or she is expected to maintain high "activity"—including stop-and-frisks—but, paradoxically, to record fewer actual crimes.</blockquote><br />
<br />
Even more frightening is to listen via the streaming audio to [http://www.thisamericanlife.org/radio-archives/episode/414/right-to-remain-silent The Right to Remain Silent] (episode number 414 of the NPR program, This American Life):<br />
<blockquote><br />
<br />
For 17 months, New York police officer Adrian Schoolcraft recorded himself and his fellow officers on the job, including their supervisors ordering them to do all sorts of things that police aren't supposed to do. For example, downgrading real crimes into lesser ones, so they wouldn't show up in the crime statistics and make their precinct look bad.<br />
</blockquote><br />
<br />
'''Discussion'''<br />
<br />
1. The full study on stretching may be found [http://www.usatf.org/stretchStudy/StretchStudyReport.pdf here]. Take note of the many caveats such as runners who did stretching ordinarily but were randomly assigned to forego stretching were more likely to be injured.<br />
<br />
2. There is enormous controversy regarding annual mammograms for women less than 50 years old. Assuming that mammography is not efficacious for women under 50, why would any organization keep insisting it should be done? <br />
<br />
3. [http://schoolcraftjustice.com/ Adrian Schoolcraft] is suing NYPD and Jamaica Hospital for $50 million. It is alleged that <br />
<blockquote><br />
[O]n October 31, 2009, several high ranking NYPD officials illegally entered PO Schoolcraft’s home, forcibly removed him in handcuffs, seized his personal effects, including evidence he had gathered documenting NYPD corruption, and had him admitted to Jamaica Hospital Center against his will, under the false pretense that he was “emotionally disturbed.” <br />
</blockquote><br />
<br />
As noted above, Schoolcraft had “hard” evidence--his recordings--of data manipulations. Nonetheless, in this age of electronic manipulation, should his recordings be trusted? Be sure to listen to the end of the radio program to hear the police being angry to discover his secret recording device which falls out of his pocket during the rough interrogation--only to miss another recording device in the room!<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_65&diff=10957Chance News 652010-08-12T23:29:09Z<p>PaulAlper: /* Surrogate markers */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>"All scientific work is incomplete - whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have or postpone the action that it appears to demand at a given time."</blockquote><br />
<br />
Sir Austin Bradford Hill, as quoted at [http://toxipedia.org/display/toxipedia/Sir+Austin+Bradford+Hill Toxipedia].<br><br />
Submitted by Steve Simon.<br />
----<br />
<blockquote>"His lectures were loud and entertaining. ...He took umbrage when someone interrupted his lecturing by pointing out some glaring mistake. He became red in the face and raised his voice, often to full shouting range. It was reported that on occasion he had asked the objector to leave the classroom. The expression 'proof by intimidation' was coined after Feller's lectures (by Mark Kac)." <br />
</blockquote><br />
<br />
Gian-Carlo Rota, [http://www.princeton.edu/~mudd/finding_aids/mathoral/pmcxrota.htm Fine Hall in its golden age: Remembrances of Princeton in the early fifties.]<br><br />
<br />
<blockquote>"When, as a student in 1946, I decided that I ought to learn some probability theory, it was pure chance that led me to take the book ''Theory of Probability'' by Jeffreys from the library shelf."</blockquote><br />
<br />
William Feller, as quoted in [http://www.stat.columbia.edu/~gelman/research/unpublished/feller.pdf “Not only defended but also applied”: A look back at Feller’s take on Bayesian inference], by Andrew Gelman and Christian<br />
P. Robert<br />
<br />
Submitted by Paul Alper<br />
----<br />
<blockquote>“In the dark candlelit room where they swear allegiance to FIFA, coaches and commentators have agreed that if you are a soccer person, you have to say you don’t buy into stats.”</blockquote><br />
<br />
Mark Brunkhart, president of [http://matchanalysis.com/ Match Analysis], as quoted in [http://www.nytimes.com/2010/07/09/sports/soccer/09soccerstats.html?scp=5&sq=statistics&st=cse When it comes to stats, soccer seldom counts], ''New York Times'', 8 July 2010.<br><br />
Submitted by Bill Peterson<br />
----<br />
<blockquote>“Basically, I’m not interested in doing research and I never have been. I’m interested in ''understanding'', which is quite a different thing. And often to understand something you have to work it out yourself because no one else has done it.”</blockquote><br />
<br />
David Blackwell, as quoted in <br />
[http://www.nytimes.com/2010/07/17/education/17blackwell.html?_r=1&emc=eta1 David Blackwell, scholar of probability, dies at 91],<br />
''New York Times'', 16 July 2010.<br><br />
Suggested by Priscilla Bremser<br />
----<br />
<blockquote>"It's better than Disneyland in terms of how you can take technologies and go after a resource that is thousands of years old and do so in an environmentally sound way."<br> <br />
-- Alaska Senator Lisa Murkowski to the Senate Energy Committee (7 months ago) on the science of deep-sea drilling</blockquote><br />
<blockquote>Predictable outcomes are unusual within ecological systems, while “unpredictable, chaotic events [are] usual."<br><br />
--Environmentalist Carolyn Merchant</blockquote><br />
Quoted in [http://www.thenation.com/article/36608/hole-world “A Hole in the World”], <i>The Nation</i>, July 12, 2010<br><br />
Submitted by Margaret Cibes<br />
----<br />
<blockquote>”When I teach a course on statistics (to about 300 second-year psychology students, all of whom have had several courses in introductory stats already) I start by waving a 20 euro bill around, telling them ‘if you can tell me exactly what a p-value is you get 20 euros’. Result: I always get to keep my money, because they have no clue what a p-value is.”</blockquote><br />
Blogger responding to [http://www.sciencenews.org/view/feature/id/57091/title/Odds_are,_its_wrong “Odds Are, It's Wrong: Science fails to face the shortcomings of statistics”], <i>Science News</i>, March 27, 2010.<br><br />
<br />
<blockquote>“The practitioner [of the religion of Statistics] engages in a ritual known as ‘hunting for p values.’ …. Once the calculations are completed, … the practitioner must be prepared to suffer the wrath of the angry gods of Statistics. If the <i>p</i> value is bigger than .05, he will not be allowed to publish. It may even mean running another experiment. If he is clever, the practitioner may find ways to modify the original data (leaving out numbers that are obviously wrong is the most common practice) and invoke the gods again. …. Sometimes, however, no manipulation of the data short of outright fraudulent misrepresentation will produce a <i>p</i> value less than .05. The sensible practitioner will remember that we live in an unfair and irrational world and accept his defeat.”</blockquote><br />
David Salsburg, in [http://www.jstor.org/pss/2683942 “The Religion of Statistics as Practiced in Medical Journals”], <i>The American Statistician</i>, August 1985.<br><br />
See also [http://www.jstor.org/pss/2684562 “Comment on ‘The Religion of Statistics’”], <i>The American Statistician</i>, August 1986.<br><br />
<blockquote>“[T]he difference between ‘significant’ and ‘not significant’ is not itself statistically significant.”</blockquote><br />
Andrew Gelman and Hal Stern, in an article of the same title[http://www.stat.columbia.edu/~gelman/research/published/signif4.pdf], <i>The American Statistician</i>, November 2006.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
Recent John Paulos Stories<br />
<br />
[How Much Oil's Spilling? It's Not Rocket Science http://abcnews.go.com/Technology/WhosCounting/]<br />
<br />
==Forsooth==<br />
The following Forsooths are from the RSS NEWS June 2010<br><br />
<br />
<blockquote><br />
<p>Labour's betrayal of British workers. Nearly every one of 1.67m jobs created<br />
since 1997 has gone to a foreigner.<br />
</p><br />
<br />
<p>Immigration was at the centre of the election campaign today as it emerged that virtually every extra job created under Labour has gone to a foreign worker.</p><br />
<br />
<p>Figures suggested an extraordinary 98.5 per cent of 1.67 million new posts were taken by immigrants.</p><br />
<br />
<p>The ONS figures show the total number of<br />
people in work in both the private and<br />
the public sector has risen from around<br />
25.7 million in 1997 to 27.4 million at the<br />
end of last year, an increase of 1.67 million.</p><br />
<br />
<p>But the number of workers born abroad<br />
has increased dramatically by 1.64 million<br />
from 1.9 million to 3.5 million.</p><br />
<br />
<div align="right"> <br />
[http://www.dailymail.co.uk/news/election/article-1264333/GENERAL-ELECTION-2010-Under-Labour-nearly-UK-jobs-taken-foreigners.html Daily Mail, 8 April 2010] </div><br />
</blockquote><br />
<br />
<blockquote><br />
<p>The English language currently comprises roughly a million words. Discounting new <br />
words that are added every day, and those occasionally lost to posterity, the possibility <br />
of forming a three-word combination is therefore a million cubed, or a quadrillion--that's followed by 216<br />
zeros.</p><br />
<br />
<div align="right">The Guardian, 21 August 2009 </div><br />
</blockquote><br />
<br />
Submitted by Laurie Snell<br />
<br />
-----<br />
<blockquote>”There has always been a question about just how much of a forecasting mechanism markets are. Hence the saying that stocks have correctly predicted 15 of the past nine recessions.”</blockquote><br />
<br />
<div align=right>[http://www.time.com/time/magazine/article/0,9171,2005849,00.html “With Stocks, It’s Not the Economy”], <i>TIME</i>, August 2, 2010</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
Some responses to a Josephson Institute survey of American public and private high-school students, [http://charactercounts.org/programs/reportcard/2008/index.html “The Ethics of American Youth: 2008”]:<br />
<blockquote>30 percent said that they had <i>stolen from a store</i> within the past year.<br><br />
42 percent said that they <i>sometimes lie to save money</i>.<br><br />
64 percent said that they had <i>cheated on a test</i> during the past year.<br><br />
26 percent admitted that they had <i>lied on at least one or two questions on the survey</i>.<br><br />
93 percent said that they were <i>satisfied with their personal ethics and character</i>.<br><br />
77 percent said that <i>when it comes to doing what is right, I am better than most people I know</i>.<br></blockquote><br />
The 2008 survey had 29,760 respondents, although not all respondents replied to all questions. The website has links to the original questions and to demographic background data for every question.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Return on investment in college==<br />
Union, RPI rank high on education value.<br><br />
by Caitlin Tremblay, ''Daily Gazette'' (Schenectady, NY), 30 June 2010, p. A5<br />
<br />
The article reports that that two local colleges (Union College and Rensselaer Polytechnic Institute) “are listed among New York state’s and the nation’s best colleges for making back the money spent on a bachelor degree, according to a study by the website PayScale.com …Payscale, a compensation research website, took the price of the schools’ degree and compared it to the average income of graduates to calculate a ‘return on investment.’ Only those with undergraduate degrees and full-time hourly or salaried jobs were included…Topping Payscale’s list are Massachusetts Institute of Technology (annual ROI of 12.6 percent), California Institute of Technology (12.6 percent) and Harvard University (12.5 percent).”<br />
<br />
The website [http://www.payscale.com/education/average-cost-for-college-ROI Paycale.com] (which also explains the methodology) asserts that “A return on investment (ROI) calculation tells you what you get back for what you spend - and it's a great way to compare college costs…PayScale helps you figure out which school's tuition costs will return the biggest dividends for you after graduation.”<br />
<br />
'''Discussion Questions''' <br />
<br />
With the help of the Payscale.com website [http://www.payscale.com/education/compare-college-costs-and-ROI methodology description]:<br />
<br />
<ol><br />
<li>Critique, from a statistical perspective, the use of the results of this study in comparing colleges with regard to assessing “what you get back for what you spend.”<br />
<br />
<li>How might the validity of such a study be improved and, if implemented, how would this impact any reservations you might have about the conclusions that you might draw?<br />
<br />
<li>Comment on any other aspects of the underlying methodology and how it might be improved.<br />
</ol><br />
<br />
Submitted by Gerry Hahn<br />
<br />
==Paul the octopus plumps for Spain==<br />
[http://soccernet.espn.go.com/world-cup/story/_/id/807251/ce/uk/?cc=5901&ver=us ESPN soccernet], 9 July 2010<br />
<br />
Spain will defeat Netherlands in Sunday's World Cup final, according to the latest prediction from Paul the psychic octopus.<br />
<br />
To intense media interest on Friday morning, Paul, who has an unblemished record in the tournament so far, picked Spain as the victors in the Johannesburg final and also predicted that Germany will defeat Uruguay in Saturday's third-place play-off.<br />
<br />
The decision was welcomed in Spain - who were also tipped by Paul to defeat his home country, Germany, in the semi-finals - with Marca's website leading with the story of how el pulpo Paul predicted that Spain would be campeones.<br />
<br />
Paul has achieved global fame after correctly predicting the results of all of Germany's games at the tournament in South Africa. In order to harness his powers, his keepers at Sea Life Oberhausen present Paul with the choice of two glass boxes, both containing a mussel but each bearing the flag of a different country.<br />
<br />
The odds of Paul correctly predicting Germany's results so far are 1 in 64 and he proved correct once again when tipping Spain to beat Joachim Low's side in the semi-final, which they duly did thanks to a header from Carles Puyol.<br />
<br />
Many German fans were unhappy with Paul's decision to plump for Spain and, fearing a backlash, Spanish Prime Minister Jose Luiz Rodriguez Zapatero has joked he will offer state protection to Paul!<br />
<br />
'''Discussion'''<br />
<br />
Read more about Paul [http://en.wikipedia.org/wiki/Paul_the_Octopus here] and see if you would trust Paul in your bets.<br />
<br />
Submitted by Laurie Snell and suggested by Dan Rockmore<br />
<br />
==A golf oddity==<br />
[http://online.wsj.com/article/SB10001424052748704075604575357334124805788.html?KEYWORDS=JPN “Paul Goydos and the Odds of Shooting 59”]<br><br />
by John Paul Newport, <i>The Wall Street Journal</i>, July 10, 2010<br><br />
<br />
In a July 8, 2010 golf tournament, Paul Goydos shot a 59, only the fourth such score in 612,489 rounds on the PGA Tour. <br />
<blockquote>Those odds of 153,123 to 1 compare with 2,139 to 1 for baseball no-hitters and 21,084 to 1 for perfect games during the same period. A 59 is 1/300th as likely as a hole-in-one on the PGA Tour; [it is] 1/25th as likely as a double eagle.</blockquote> <br />
Submitted by Margaret Cibes<br />
<br />
==Tuesday’s child==<br />
<br />
[http://answers.google.com/answers/threadview?id=145411 The famous nursery rhyme] proclaims: “Tuesday’s child is full of grace.” Well, factoring in Tuesday for a birth date as discussed in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_64#A_probability_puzzle Chance News 64] and [http://www.stat.columbia.edu/~cook/movabletype/archives/2010/05/hype_about_cond.html Andrew Gelman’s blog] produced a flood of comments. <br />
<br />
Without Tuesday muddying the waters, the well-known answer to<br />
<blockquote>I have two children.<br><br />
One is a boy.<br> <br />
What is the probability that I have two boys?<br />
</blockquote><br />
is 1/3, rather than 1/2 as many are prone to say. William Feller in his famous book (''Introduction to Probability Theory and Its Applications, Volume I'', Third Edition, page 117) says the value of 1/2 is the solution to a much simpler problem: “A boy is chosen at random and comes from a family with two children; what is the probability that the other child is a boy?” He explains why: The 1/3 “might refer to a card file of families,” while the 1/2 “might refer to a file of males. In the latter, each family with two boys will be represented twice, and this explains the difference between the two results.”<br />
<br />
Many of the comments focused on the intuitively irrelevant aspect of Tuesday and yet, a careful laying out of the sample space indicates that the day of the week for the birth of a boy turns out to be relevant. Some of the comments tried to explain the cognitive dissonance by referring to similarities to the so-called Monty Hall Problem, in the sense that available information needs to be accounted for.<br />
<br />
With Tuesday thrown into the mix, the answer to <br />
<blockquote>I have two children.<br><br />
One is a boy born on Tuesday. <br><br />
What is the probability that I have two boys?<br />
</blockquote><br />
<br />
surprisingly, turns out to be 13/27, which is close to 1/2, the answer to the simpler problem.<br />
<br />
Consider a different physical situation, where “boy” now represents a successful knee operation and “girl” now represents an unsuccessful knee operation--we have, after all, but two knees. Ignoring the “Tuesday” aspect, knowing there is a successful knee operation implies a 1/3 chance of two successful knee operations. But this seems especially the wrong-way round because knowing of an ''unsuccessful'' knee operation implies a 2/3 chance of a successful knee operation. <br />
<br />
When “Tuesday” is added to knee replacement, the implication is closer to 1/2. In fact if we recorded time of day to the nearest minute of the day, rather than to the particular day of the week, we would be even much closer to 1/2. But that is bothersome too because this allows for manipulation of the data keeping/presentation merely by tacking on what might be deemed a "spurious" variable that can take on many values. <br />
<br />
'''Discussion''' <br />
<br />
Expanding on Feller’s explanation, what is the proper “card file” to use here?<br />
<br />
Submitted by Paul Alper<br />
<br />
DISCUSSION:<br />
<br />
Perhaps we really need to be asking, “How did we obtain the information regarding Tuesday.” If you tell me that your license plate number is some random license-plate-like number, I won’t find it surprising. But if I ask you whether your license plate number is some random number that I thought up and you say “yes”, I’ll be highly surprised. (The license plate example is based on what Richard Feynman was said to use when teaching physics.)<br />
<br />
The same sort of thing may be happening here in a more subtle way. As Paul pointed out, if we add “minute of the day” to the information and '''if we use the same logic''', the probability approaches 0.5.<br />
<br />
But the boy had to be born at some particular time, so if the father merely supplies whatever that time happened to be, is he giving me any useful information? On the other hand, if I ask whether one of the children was a boy born on Tuesday, his “yes” does supply information.<br />
<br />
Above discussion submitted by Emil Friedman<br />
<br />
==Placing great stock in stock software ==<br />
[http://online.wsj.com/article/SB10001424052748703834604575365310813948080.html?KEYWORDS=scott+patterson “Letting the Machines Decide”]<br><br />
by Scott Patterson, <i>The Wall Street Journal</i>, July 13, 2010<br><br />
<br />
The author describes a small ($7 million) New York hedge fund, Rebellion, that has been using an artificial-intelligence program, “Star,” to invest in stocks since 2007. Its conservatively traded portfolio has beat the S&P 500 by an average of 10% per year (after fees).<br> <br />
<br />
Run by a “small team of twentysomething math and computer whizzes,” Star bases its buy/sell/hold recommendations on about 30 factors and more than 10 years of historical market data and adjusts its strategy on its own when the portfolio is underperforming.<br><br />
<br />
The company claims that a Rebellion human trader always follows Star’s recommendations. One member of the Rebellion team stated that, even when worried about a Star artificial-intelligence recommendation, <br />
<blockquote>I’ve learned not to question the AI [rtificial] I[ntelligence].</blockquote><br />
One blogger commented, “I hope they have the plug on a short leash so it can be pulled at a moment’s notice.” Another stated, “[T]he AI is only as good as the person designing it, and humans make mistakes.” On the other hand, a third blogger felt that “the biggest advantage to AI is the fact that it is not emotional, which can trip up many investors.”<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Loss aversion and streaks==<br />
Author Michael Shermer pens a [http://www.scientificamerican.com/author.cfm?id=597 column] for ''Scientific American'' and has written several useful books on "skepticism" and science. <br />
<br />
In his recent book ([http://www.michaelshermer.com/the-mind-of-the-market/ ''The Mind of the Market''], Times Books, 2007) on how evolution has shaped human economic behavior, we find the following passage (p. 93):<br />
<br />
<blockquote><br />
Gamblers, for example, are highly sensitive to losses, but not in the way you might think. They tend to follow a losing hand by placing bigger bets, and turn conservative after a winning hand by placing smaller bets. One rationale for this strategy is "double up to catch up"--no matter how many losses in a row, if you double the bet each time, you will get back all of your money when you eventually do win. But most gamblers tend to underestimate the number and length of losing streaks. <br><br />
...More important, gamblers also tend to underestimate the number and length of winning streaks and lose out on the reward of placing larger bets during them. Of course, even with an optimal betting strategy that plays to win every hand, and keeping loss aversion in check, if you play long enough you will lose because of the slight edge to the house built into the rules of the game. But casinos make even more money than the house percentage would predict because of our loss aversion.<br />
</blockquote><br />
<br />
'''Discussion Questions'''<br />
<br />
1. What do you think Shermer means here? Is it possible for players to detect when they are in the midst of "winning streaks" while playing randomly-determined games, and win more money as a result?<br />
<br />
2. Do casinos win extra money from players who simply run out of funds before their luck can even out? Assuming each individual play has the same house edge and the bet amount is the same, would the casino care if one person placed a series of 100 bets rather than 100 people placing 1 at a time?<br />
<br />
Submitted by Greg Bart<br />
<br />
== A penchant for perfection ==<br />
An amateur golfer from Stockton, California recently made local headlines [http://www.recordnet.com/apps/pbcs.dll/article?AID=/20100715/A_SPORTS/7150330/-1/a_comm01] by sinking his 16th career hole-in-one at a tournament in Reno. Rod Souza Sr., a 60-year old retired Fire Department Captain attributes his success to two things: "frequency of play and luck". According to ''Golf Digest'', the odds of an amateur golfer hitting a hole-in-one on a given hole are 1 in 12,750. <br />
<br />
'''Discussion Questions:'''<br />
<br />
1) In the article, Mr. Souza tells reporters that he has been playing golf for over 40 years, averaging 3-4 rounds per week during this time. Suppose that he averages 3.5 rounds per week and that a round consists of 18 holes. If Mr. Souza was relying on "luck" alone, how many hole-in-ones should he expect to have after 40 years of playing golf?<br />
<br />
2) What is the probability that Mr. Souza would have made 16 or more hole-in-ones if he was relying on chance alone? <br />
<br />
3) Based on your calculation in question 2, do you think Mr. Souza has shown an unusually high "penchant for perfection"?<br />
<br />
Submitted by John Mayberry<br />
<br />
==Three recent John Paulos stories==<br />
[http://abcnews.go.com/Technology/WhosCounting/oil-spilling-gulf-mexico-bp-basic-calculations/story?id=10705575 How Much Oil's Spilling? It's Not Rocket Science]<br><br />
[http://abcnews.go.com/Technology/WhosCounting/reasons-parity-puzzles-fun/story?id=10522287 Five or Six Reasons Why Parity Puzzles Are Fun]<br><br />
[http://abcnews.go.com/Technology/WhosCounting/medical-statistics/story?id=9460557 Medical Statistics Don't Always Mean What They Seem to Mean]<br><br />
<br />
'''Discussion'''<br><br />
Choose one of these stories and see if you agree with this it.<br><br />
Submitted by Laurie Snell<br />
<br />
==Statistical frustration==<br />
The headline of [http://www.nytimes.com/2010/08/10/health/research/10spinal.html?ref=gina_kolata Gina Kolata’s New York Times article] is “Spinal-Fluid Test Is Found to Predict Alzheimer’s.” The abbreviated reprint in the Minneapolis Star Tribune is “Spinal test can detect Alzheimer’s accurately.” Someone who is not connected with the study in the Archives of Neurology says, “This is what everyone is looking for, the bull’s-eye of perfect predictive accuracy.”<br />
<br />
Naturally, a closer look is less positive. The only numbers in the abbreviated reprint were: “The new study included more than 300 patients in their 70s, 114 with normal memories, 200 with memory problems and 102 with Alzheimer’s disease.” That is, a non-NYT reader would know only how many were in each arm of the study and no idea of the numerical results. <br />
<br />
The NYT reader would find an additional paragraph (actually six in all): “Nearly every person with Alzheimer’s had the characteristic spinal fluid protein levels. Nearly three quarters of people with mild cognitive impairment, a memory impediment that can precede Alzheimer’s, had Alzheimer’s-like spinal fluid proteins. And every one of those patients with the proteins developed Alzheimer’s within five years. And about a third of people with normal memories had spinal fluid indicating Alzheimer’s. Researchers suspect that those people will develop memory problems.”<br />
<br />
'''Discussion Questions'''<br />
<br />
1. The word “accuracy” is ambiguous because of the different types of errors in medical testing, Prob(no disease|test+) and Prob(disease|test-). Noting that no efficacious treatment exists at present, which error seems more serious?<br />
<br />
2. From the results stated in the NYT, does “bull’s-eye of perfect predictive accuracy” seem warranted?<br />
<br />
3. The Minneapolis Star Tribune cut out the final six paragraphs of Kolata’s NYT article. Give a justification and a criticism for the abbreviation.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Surrogate markers==<br />
[http://mdwhistleblower.blogspot.com/2010/08/evidence-based-medicine-in-disguise.html Evidence-based medicine in disguise: Beware the surrogate!] <br><br />
by Michael Kirsch, MD Whistleblower blog, 1 August 2000<br />
<br />
Dr. Michael Kirsch is a gastroenterologist who writes an interesting blog. His masthead proclaims<br />
<br />
<center>[[Image:whistleblower.gif]]</center><br />
<br />
In the post referenced above he writes, <br />
“A surrogate marker is an event or a laboratory value that researchers hope can serve as a reliable substitute for an actual disease.” He believes “A common practice and serious flaw in medical research is to rely upon a surrogate marker when studying a disease.” Surrogate markers are relied upon because “It is much easier and cheaper for researchers to measure surrogates than actual disease events.” Further, “Surrogate research is valid if the surrogate truly represents the disease. Often, this assumption is questionable or outright false.”<br />
<br />
Much of evidence-based medicine depends on the use of statistics and the trick is to measure that which is consequential rather than that which is convenient, a.k.a., a surrogate marker; unfortunately, that could be difficult. His first example is medication to lower cholesterol:<br />
<blockquote><br />
What could be simpler than measuring blood cholesterol levels? In contrast, it would be a very tough slog to show that a cholesterol-lowering drug reduced heart failure or mortality rates. With a surrogate, medical studies can be completed much more rapidly, in contrast to studying actual diseases, which can take a decade or more to complete. By then, the findings may no longer be relevant. Surrogate research is also much less expensive to perform.<br />
<br><br><br />
Surrogate results have flashy marketing appeal because their findings can be expressed in catchy headlines that extrapolate the actual conclusions.<br />
</blockquote><br />
<br />
He even criticizes his own field of gastroenterology:<br />
<blockquote><br />
...gastroenterologists remove colon polyps with enthusiasm and zeal. Polyps are not diseases. They are surrogates for colon cancer. We hope and believe that when we remove pre-cancerous polyps that we are reducing your risk of colon cancer. Interestingly, there is no double-blind placebo controlled trial (the gold standard of medical research) that establishes that colonoscopy reduces colon cancer. Just because it sounds logical, doesn’t mean that it’s true.<br />
</blockquote><br />
<br />
'''Discussion Questions'''<br />
<br />
1. A reader to Kirsch’s blog wrote, “Perhaps there needs to be a distinction between surrogates, precursors, and prerequisites.” Read Kirsch’s response and give some of your own examples of possible distinctions among the three terms.<br />
<br />
2. Surrogate markers arise in many fields besides medicine. For example, spirituality is not easy to measure and instead church attendance might be considered a surrogate marker. Defend and criticize church attendance as a useful surrogate marker. Put forward a better surrogate marker.<br />
<br />
3. Marital fidelity is likewise difficult to assess. Suggest some surrogate markers for marital fidelity.<br />
<br />
4. Intelligence, a complex characteristic, is often measured by the surrogate marker, an IQ test. Defend and criticize the IQ test as a surrogate marker for intelligence.<br />
<br />
5. The field of nutrition is overflowing with surrogate markers which are often called “risk factors.” Suggest some risk factors which are tightly connected to a disease and some risk factors which are tenuously connected to a disease.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_64&diff=10723Chance News 642010-05-22T17:07:07Z<p>PaulAlper: /* Miscellaneous studies */</p>
<hr />
<div>==Quotations==<br />
<blockquote>We tolerate the pathologies of quantification — a dry, abstract, mechanical type of knowledge — because the results are so powerful. Numbering things allows tests, comparisons, experiments. Numbers make problems less resonant emotionally but more tractable intellectually. In science, in business and in the more reasonable sectors of government, numbers have won fair and square.<br> --Gary Wolf<br />
</blockquote><br />
<br />
Writing in [http://www.nytimes.com/2010/05/02/magazine/02self-measurement-t.html?pagewanted=1&hpw The data-driven life], ''New York Times'', 26 April 2010<br />
<br />
Submitted by Bill Peterson<br />
----<br />
<blockquote>The skepticism that people like Gregg [US Senator from NH] apply to statistics, if applied to other sciences, would get them lumped with the anti-vaccinationists and the homeopaths. <br> --Jordan Ellenberg<br />
</blockquote><br />
<br />
Writing in [http://www.washingtonpost.com/wp-dyn/content/article/2010/04/30/AR2010043001862.html?hpid=opinionsbox1 The census will be wrong. We could fix it.] ''Washington Post'', 1 May 2010<br><br />
(This article was recommended by Laura Chihara on the Isolated Statisticians list.)<br />
----<br />
<blockquote>In the world of cancer research, there is something called a Kaplan-Meier curve, which tracks the health of patients in the trial of an experimental drug. In its simplest version, it consists of two lines. The first follows the patients in the “control arm,” the second the patients in the “treatment arm.” …. Seven years ago … a team presented the results of a colorectal-cancer drug trial at the annual meeting of the American Society of Clinical Oncology …. The lead … researcher took the audience through one slide after another … laying out the design and scope of the study, until he came to the crucial moment: the Kaplan-Meier. At that point, what he said became irrelevant. The members of the audience saw daylight between the two lines, for a patient population in which that almost never happened, and they leaped to their feet and gave him an ovation. Every drug researcher in the world dreams of standing in front of thousands of people at ASCO and clicking on a Kaplan-Meier like that.<br><br />
--Malcolm Gladwell</blockquote> <br />
Writing in [http://www.newyorker.com/reporting/2010/05/17/100517fa_fact_gladwell “The Treatment”], <i>The New Yorker</i>, May 17, 2010 (Full text may require subscription.)<br><br />
<br />
See a Vanderbilt PowerPoint[http://biostat.mc.vanderbilt.edu/wiki/pub/Main/ClinStat/km.lam.pdf] addressing the purpose and method of the Kaplan-Meier method/chart of survival analysis.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Forsooth==<br />
<blockquote>Pitching is 80% of the game. The other half is hitting and fielding.<br><br />
--former Yankee Mickey Rivers</blockquote><br />
Quoted in [http://online.wsj.com/article/SB10001424052748703866704575224340794758622.html?KEYWORDS=Michael+Salfino “Is Greinke the Unluckiest Pitcher Ever?”]<br />
<i>The Wall Street Journal</i>, May 5, 2010<br><br />
<br />
See more great quotes online at [http://mickeyrivers.com/quotes_baseball.shtml "Mickey Rivers' Words of Wisdom About Baseball"].<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Odds are, it’s wrong--Part II==<br />
An entry in [http://www.causeweb.org/wiki/chance/index.php/Chance_News_63#Odds_are.2C_it.27s_wrong Chance News 63] presented a Science News article by Tom Siegfried. The article, which focuses on statistics used in the medical field, may be found [http://www.sciencenews.org/view/feature/id/57091/title/Odds_Are,_Its_Wrong here] and is worth some elaboration; be sure to read the [http://www.sciencenews.org/view/feature/id/57091/title/Odds_Are,_Its_Wrong#comment_editorcomments comments reacting to what Siegfried writes.] There you will find mention of circumcision, condoms, defense of statistics in medicine, praise for the author, condemnation of the author--and somehow, reference to Scott Reuben, who faked data for Pfizer and Merck (see [http://www.causeweb.org/wiki/chance/index.php/Chance_News_45#Serious_Medical_Fraud Serious medical fraud] in Chance News 45).<br />
<br />
Siegfried’s main contention is that despite its prevalence in the medical sphere (and dominance elsewhere as well), Fisher’s p-value approach is inadequate and misleading at best. Because of this “p-value mania,” Siegfried quotes two researchers who claim “that in modern [medical] research, false findings may be the majority or even the vast majority of published research claims,” and “There are more false claims made in the medical literature than anybody appreciates,” respectively.<br />
<br />
Criticism of p-value is hardly new. Put “criticism of p-value” into a browser and you will get 4,520,000 hits, many of which are more informative than Siegfried’s article. Try [http://ije.oxfordjournals.org/cgi/content/full/32/5/699 The P-value, devalued] from the ''International Journal of Epidemiology'' as an example.<br />
<br />
'''Discussion'''<br />
<br />
1. To see why critics of p-value say it is the wrong-way round, consider <br />
Prob ( brown eyes | Costa Rican) and Prob (Costa Rican | brown eyes). Compare with<br />
Prob (data | Null Hypothesis is true) and Prob (Null Hypothesis is true | data). For an interesting illustration of the difference between these conditional probabilities regarding the O.J. Simpson murder case see [http://opinionator.blogs.nytimes.com/2010/04/25/chances-are/?scp=1&sq=strogatz%20oj%20simpson&st=cse Steven Strogatz’s NYT article] (25 April 2010).<br />
<br />
2. Critics of p-value say that the above #1 is not strong enough of a criticism because p-value deals not with “data” that actually occurred but with “data at least this extreme.” Why is this a potent criticism?<br />
<br />
3. Siegfried rightfully refers to “randomized, controlled clinical trials that test drugs for their ability to cure or their power to harm” as the “gold standard” for medical research. “Such trials assign patients at random to receive either the substance being tested or a placebo.” However, see [http://opinionator.blogs.nytimes.com/2010/05/03/enhancing-the-placebo/ Judson’s NYT article, Enhancing the Placebo] (3 May 2010), which discusses how non-placebo a placebo can be. What does this do to clinical trials and the gold standard?<br />
<br />
4. Siegfried suggests that Bayesian inference is preferable to the frequentist p-value approach of Fisher. If this is so, why is it that p-value approach is so dominant, long after Fisher himself died?<br />
<br />
Submitted by Paul Alper<br />
<br />
==Health insurers finagling fees?==<br />
[http://online.wsj.com/article/SB10001424052748704866204575224550122571136.html?KEYWORDS=avery+johnson&mg=com-wsj “For WellPoint, Math Error Spurs More Scrutiny”]<br><br />
by Avery Johnson, <i>The Wall Street Journal</i>, May 5, 2010<br><br />
<br />
The health insurer WellPoint, an affiliate of Anthem Blue Cross, has decided to withdraw its request for up to a 39% price increase on individual plans in California.<br><br />
<br />
The decision followed an actuarial consultant’s report about math errors in the company’s calculations. Alleged mistakes included overestimating future medical costs and double-counting the effect of aging on its policyholders.<br> <br />
<br />
The overestimation is thought to be related to a new requirement that health insurers spend “80% of their premium revenues on healthcare for plans that cover individuals and small businesses, and 85% for policies with large employers.”[http://articles.latimes.com/2010/may/01/business/la-fi-anthem-20100501]<br><br />
<br />
Health and Human Services Secretary Kathleen Sebelius has asked a nation-wide review of the health-related data on which costs are based, and she noted that $250 million has been allocated to states for that purpose.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Girls becoming less careful drivers==<br />
[http://online.wsj.com/article/SB10001424052748704866204575224110235731780.html?KEYWORDS=joseph+b+white “Do Girls Speed More Than Boys?”]<br><br />
by Joseph B. White and Anjali Athavaley, <i>The Wall Street Journal</i>, May 5, 2010<br><br />
<br />
Allstate Foundation has sponsored a survey that found that young women are not necessarily more responsible than young men – at least in their driving habits. An Allstate spokesman stated, “It would be fair to say the gap is closing,” although “teenage girls continue to be a better risk than boys.”<br><br />
<br />
The data came from online interviews with 1,063 teens across the country in May 2009. About half of the girls felt that they are more likely to drive 10 mph over the speed limit or to phone/text while driving, compared to fewer than 40% of boys for each activity.<br><br />
<br />
State Farm, the nation’s largest insurance company, charges 40% more for teenage boys than girls, down from a 1985 gap of 61%. While the company is raising the rates for teenage female drivers, it says that it is raising them based on claims experience and other factors, not these survey results.<br><br />
<br />
For the current report, see [http://www.allstate.com/foundation/teen-driving/Shifting-Teen-Attitudes.aspx “Shifting Teen Attitudes: 2009 State of Teen Driving”]. For 2005 report, see [http://www.allstate.com/foundation/teen-driving/chronic-report.aspx “Chronic - A Report on the State of Teen Driving”]. Unfortunately, neither the questionnaires, nor any raw data, appears to be available online.<br><br />
<br />
<b>Discussion</b><br><br />
<br />
1. What additional information about the survey would you like to know in order to draw any conclusion about the driving habits of all teenage girls and boys across the country?<br><br />
<br />
2. Do you believe that self-reporting by teenagers, in general is reliable? Would you expect a difference in relying on teen boys’ versus teen girls’ responses?<br><br />
<br />
3. In the article, Progressive Direct quoted 6-month premiums for a boy and a girl in identical situations, including one speeding ticket apiece in the last 3 years, at $2,938 and $2,627, respectively. By what percent does the boy’s Progressive premium exceed the girl’s Progressive premium? How does it compare with Allstate’s 40% figure? Can you think of any reason(s) for the reported disparity? <br> <br />
<br />
4. The article referred to girls as becoming more “aggressive” drivers. <i>If</i> this is true, can you think of any reason(s) for this?<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Black swan author linked to black swan event==<br />
[http://online.wsj.com/article/SB10001424052748704879704575236771699461084.html?KEYWORDS=scott+patterson “Did a Big Bet Help Trigger ‘Black Swan’ Stock Swoon?”]<br><br />
by Scott Patterson and Tom Lauricella, <i>The Wall Street Journal</i>, May 10, 2010<br><br />
<br />
On May 6 the Dow Jones Industrial average fell nearly 1,000 points in less than half an hour.[http://abcnews.go.com/Business/dow-jones-dives-european-debt-scare-shakes-us/story?id=10576136]. The decline was initially attributed to a trading error in which a Citigroup trader incorrectly keyed in a “b” instead of an “m” for an intended $16 million trade of Proctor & Gamble stock. (This was referred to as a "fat finger" trading error in another article.) It was later reported by Reuters [http://www.reuters.com/article/idUSTRE6463LA20100507] that the rumor was untrue. <br><br />
<br />
Apparently one of the key factors in the May 6 stock-market “collapse” was a large trade by Universa Investments during a day when “all varieties of financial markets were deeply unsettled.” Ironically, Universa is a hedge fund advised by the author of <i>The Black Swan: The Impact of the Highly Improbable</i>.<br />
<blockquote>The trade by Universa, a hedge fund advised by Nassim Taleb … led traders on the other side of the transaction … to do their own selling to offset some of the risk …. The working theory among traders and others involved in the exchange meltdown is that the "Black Swan"-linked fund may have contributed to a "Black Swan" moment, a rare, unforeseen event that can have devastating consequences.</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
==If you take away my time for your research, you owe me ten bucks==<br />
<br />
[http://www.stat.columbia.edu/~cook/movabletype/archives/2010/05/63000_worth_of.html $63,000 worth of abusive research . . . or just a really stupid waste of time?] Andrew Gelman on his Statistical Modeling, Casual Inference, and Social Science blog.<br />
<br />
Two researchers, Katherine L. Milkman of the University of Pennsylvania and Modupe N. Akinola of Columbia University, wanted to use email to find out patterns in the responsiveness of professors to a request for their time. They sent out emails to 6,300 professors asking for an appointment for help in one of two possible time frames. When the professors responded, they recorded the results and then canceled the request for the appointment. Later they sent an email explaining that the original request was part of a research study.<br />
<br />
One of the people who received this request, Andrew Gelman, did not take kindly to being part of a research study without first getting his consent and asked on his blog for $10 compensation. Later, he [http://www.stat.columbia.edu/~cook/movabletype/archives/2010/05/another_update.html softened his anger about the research].<br />
<br />
The Chronicle of Higher Education has a [http://chronicle.com/article/Academe-Hath-No-Fury-Like-a/65466/ story] on this research and the fuss it created in the academic community, though you may need a subscription to read the full article.<br />
<br />
===Questions===<br />
<br />
1. This research involved deception. Do you feel that deception should ever be allowed in ethical research. If so, under what conditions?<br />
<br />
2. The study did not provide informed consent prior to getting subject participation in the study. Did that make the study unethical?<br />
<br />
3. What would be the appropriate response to a subject who protested that he/she did not wish to participate in the research?<br />
<br />
4. Is there a different way this study could have been conducted that would have avoided this controversy?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Miscellaneous studies==<br />
<b>“Beer and Mosquitoes”</b><br><br />
Research based on 43 West African men and 4,300 mosquitoes concluded that “mosquitoes preferred the odor of beer drinkers to outdoor air by a margin of nearly 2 to 1.”<br><br />
For a brief summary of results, see this topic[http://online.wsj.com/article/SB10001424052748704093204575216162028422760.html?KEYWORDS=jeremy+singer-vine] as one section of Jeremy Singer-Vine’s May 4 summary of current research projects, a regular feature of <i>The Wall Street Journal</i>. For the full May 2010 report of results, see [http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0009546 “Beer Consumption Increases Human Attractiveness to Malaria Mosquitoes”], which includes an ethics statement, as well as methodology and statistics.<br><br />
<br />
<b>“The Falling Time Cost of College”</b><br><br />
Research[http://econ.ucsb.edu/~babcock/college_time_use_11_09restat.pdf] based on a December 2009 study of the “academic time investment” of full-time U.S. college students for the period 1961-2003 showed a decline from 40 to 27 hours week. The report includes discussions of framing effects, representativeness, and composition effects. The authors have another December 2009 report on this topic, [http://www.econ.ucsb.edu/~babcock/LeisureCollege2.pdf “Leisure College, USA”].<br><br />
<br />
<b>"The Power of Lucky Charms"</b><br><br />
Several research results[http://online.wsj.com/article/SB10001424052748703648304575212361800043460.html?KEYWORDS=Carl+Bialik] about the effect of beliefs about luck on performance are summarized by Carl Bialik, who indicates that a new research report on this topic is expected in June. For a critique of Bialik's article and that June report, see [http://www.causeweb.org/wiki/chance/index.php/Chance_News_63#Lucky_charms_and_disappointing_journalism Lucky charms and disappointing journalism]. For a related online blog by Bialik, with references to even more studies, see [http://blogs.wsj.com/numbersguy/mathematicians-take-on-luck-930/ "Mathematicians Take On Luck"].<br><br />
<br />
<b>“Piano stairs”</b><br><br />
Research[http://www.youtube.com/watch?v=2lXh2n0aPyw] showed that the redesign of a subway station’s stairs led to more people choosing the stairs than the escalator. Enjoy the YouTube video!<br><br />
<br />
Submitted by Margaret Cibes</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_59&diff=9879Chance News 592009-12-30T00:16:17Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<blockquote> I wish I could say, well, I told people correlation doesn't equal causation back in 1989, so I don't have to say it again.</blockquote><br />
<br />
Joe Palca, NPR science correspondent, lamenting the lay public's continual lack of understanding of how science progresses; this appeared in an article by Julia Galef entitled "Uncertainty in Science, It's a Feature, Not a Bug," [http://www.thehumanist.org/humanist/10_jan_feb/Galef.html''The Humanist'',] January-February 2010.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth== <br />
<br />
==Calculating high school dropout rates==<br />
<br />
[http://voices.kansascity.com/node/7049 KC School District's dropout rate doesn't add up]. Michael McShane, The Kansas City Star.<br />
<br />
The Kansas City, Missouri school district had some amazing statistics to brag about.<br />
<br />
<blockquote>The Kansas City School District recently announced a dropout rate of 5.9 percent. Compared with the dropout rate of 41.2 percent reported a year ago, it appeared as if the district was moving by leaps and bounds in the right direction to correct the problem.</blockquote><br />
<br />
These results, however, appear to be incorrect.<br />
<br />
<blockquote>The Missouri Department of Education says when the Kansas City School District’s Class of 2009 started eighth grade in the fall of 2004 it had 2,629 members. When that class graduated this spring, 1,032 students earned diplomas. It doesn’t take a degree in mathematics to recognize that does not add up.</blockquote><br />
<br />
The calculation of a dropout rate is not too difficult.<br />
<br />
<blockquote>It is a simple mathematical formula; take the total number of students who graduate and divide it by how many students started in eighth grade. If necessary, adjust that number for demographic movement trends and with a No. 2 pencil and a scientific calculator, anyone at home can estimate the graduation rate.</blockquote><br />
<br />
Here are the numbers you need for the calculation.<br />
<br />
<blockquote>Let’s calculate it together. When those 2,629 eighth-graders were enrolled in the district, the total enrollment for the district was 26,968 students. When 1,032 members of that cohort earned diplomas there were 22,479 total students enrolled in the district.</blockquote><br />
<br />
If you don't account for migration, the graduation rate is 1032 / 2629 = 39%. Here's how to account for migration.<br />
<br />
<blockquote>In that same period, the overall district enrollment declined by 16.65 percent, so it’s fair to reduce the number of eighth-graders to reflect that, which we can do by multiplying by 0.8335. After those calculations, the adjusted graduation rate of the district is really 47 percent.</blockquote><br />
<br />
Part, but not all of the discrepancy, can be accounted for by a change in time frame. The 5.9% represents an annual drop-out rate, not a rate across four years, a practice that Dr. McShane derides.<br />
<br />
<blockquote>The district’s using that number as its dropout rate is the equivalent of your credit card company telling you the monthly rather than the yearly interest rate. It may make you feel better, but you’re still going to pay big.</blockquote><br />
<br />
===Questions===<br />
<br />
1. How would you convert a yearly dropout rate to a four year dropout rate?<br />
<br />
2. The adjustment for migration makes some assumptions. What are those assumptions? Are they reasonable?<br />
<br />
3. Would it make sense to compute confidence limits for the dropout rate?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Item 2==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_59&diff=9873Chance News 592009-12-29T23:26:57Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<blockquote> I wish I could say, well, I told people correlation doesn't equal causation back in 1989, so I don't have to say it again.</blockquote><br />
<br />
Joe Palca, NPR science correspondent, lamenting the lay public's continual lack of understanding of how science progresses; this appeared in an article by Julia Galef entitled "Uncertainty in Science, It's a Feature, Not a Bug," ''The Humanist'', January-February 2010.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooth== <br />
<br />
==Calculating high school dropout rates==<br />
<br />
[http://voices.kansascity.com/node/7049 KC School District's dropout rate doesn't add up]. Michael McShane, The Kansas City Star.<br />
<br />
The Kansas City, Missouri school district had some amazing statistics to brag about.<br />
<br />
<blockquote>The Kansas City School District recently announced a dropout rate of 5.9 percent. Compared with the dropout rate of 41.2 percent reported a year ago, it appeared as if the district was moving by leaps and bounds in the right direction to correct the problem.</blockquote><br />
<br />
These results, however, appear to be incorrect.<br />
<br />
<blockquote>The Missouri Department of Education says when the Kansas City School District’s Class of 2009 started eighth grade in the fall of 2004 it had 2,629 members. When that class graduated this spring, 1,032 students earned diplomas. It doesn’t take a degree in mathematics to recognize that does not add up.</blockquote><br />
<br />
The calculation of a dropout rate is not too difficult.<br />
<br />
<blockquote>It is a simple mathematical formula; take the total number of students who graduate and divide it by how many students started in eighth grade. If necessary, adjust that number for demographic movement trends and with a No. 2 pencil and a scientific calculator, anyone at home can estimate the graduation rate.</blockquote><br />
<br />
Here are the numbers you need for the calculation.<br />
<br />
<blockquote>Let’s calculate it together. When those 2,629 eighth-graders were enrolled in the district, the total enrollment for the district was 26,968 students. When 1,032 members of that cohort earned diplomas there were 22,479 total students enrolled in the district.</blockquote><br />
<br />
If you don't account for migration, the graduation rate is 1032 / 2629 = 39%. Here's how to account for migration.<br />
<br />
<blockquote>In that same period, the overall district enrollment declined by 16.65 percent, so it’s fair to reduce the number of eighth-graders to reflect that, which we can do by multiplying by 0.8335. After those calculations, the adjusted graduation rate of the district is really 47 percent.</blockquote><br />
<br />
Part, but not all of the discrepancy, can be accounted for by a change in time frame. The 5.9% represents an annual drop-out rate, not a rate across four years, a practice that Dr. McShane derides.<br />
<br />
<blockquote>The district’s using that number as its dropout rate is the equivalent of your credit card company telling you the monthly rather than the yearly interest rate. It may make you feel better, but you’re still going to pay big.</blockquote><br />
<br />
===Questions===<br />
<br />
1. How would you convert a yearly dropout rate to a four year dropout rate?<br />
<br />
2. The adjustment for migration makes some assumptions. What are those assumptions? Are they reasonable?<br />
<br />
3. Would it make sense to compute confidence limits for the dropout rate?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Item 2==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_58&diff=9845Chance News 582009-12-20T18:26:29Z<p>PaulAlper: /* N.F.L. Suspends Its Study on Concussions */</p>
<hr />
<div>==Quotations==<br />
Berkeley law professor Kevin Quinn is working on a "statistical time machine" to compare Supreme Court justices' positions across historical time periods. He emailed Carl Bialik ([http://online.wsj.com/article/SB125789565331042445.html "Statistical Time Travel Helps Answer What-Ifs"], <i>The Wall Street Journal</i>, November 12, 2009) the following quotation:<br />
<blockquote>The famous statistician George Box once wrote that "all models are wrong, but some are useful."</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
Note: I encourage you to read the article by Carl Bialik (The numbers Guy) referred to above. JLS<br />
<br />
-----<br />
<blockquote>Everyone believes in the normal law, the experimenters because they imagine that it is a mathematical theorem, and the mathematicians because they think it is an experimental fact.</blockquote><br />
<div align=right>Gabriel Lippmann (French physicist)<br><br />
in Henri Poincaré's ''Calcul de probabilités'', 1896</div align=right><br />
Submitted by Steve Simon<br />
-----<br />
<blockquote>When times are good in financial markets, we’re willing to convince ourselves that they’re good for a reason. …. “When the trend is sideways to down, they think the machine is broken,” says [technical analyst] Robert Prechter. “Jeez, it can’t be us.” ....<br><br />
Prechter readily admits that he’s far from infallible. The standard, he says he wants to be held to is similar to that of a hitter in baseball, in which batting .300 makes one a star and.400 an immortal.</blockquote><br />
<br />
<div align=right>“Riding the Waves,” <i>TIME</i>, November 30, 2009</div align=right><br />
Submitted by Margaret Cibes<br />
-----<br />
<blockquote>From principles is derived probability, but truth or certainty is obtained only from facts.</blockquote> <br />
<br />
<div align=right>Tom Stoppard</div align=right><br />
Submitted by Laurie Snell<br><br />
<br />
==Forsooth== <br />
These Forsooths are from the December 2009 RSSNews.<br />
<br />
When to undertake surveys<br />
<br />
The ideal time for monitoring walking <br />
activity is when flows are highest, That is <br />
usually in June, and is linked to good <br />
weather and longer hours of daylight.<br />
However, because most walk journeys are<br />
for utility reasons, the number of walk<br />
journeys per month does not vary greatly <br />
- unlike cycling. School holidays influence<br />
walking patterns and the purpose of a <br />
trip is often time dependent.<br />
<br />
It is uncertain to what extent the weather<br />
influences the amount of walking activity <br />
overall. It is likely that leisure walking is <br />
more strongly affected by weather <br />
conditions than walking for utility <br />
purposes. <br />
<div align=right>Department for Transport website<br><br />
October 2009</div align=right><br />
-----<br />
40% rise in swine flu deaths in<br />
48 hours as two more die<br />
The number of swine flu deaths in Scotland has soared by 40% in just 48<br />
hours, after the Scottish Government<br />
Confirmed last night that a further two<br />
people died after contracting the virus.<br />
<br />
The patients, a 48-year-old man from<br />
Greater Glasgow and Clyde and an 81-<br />
year-old Fife woman, were both carrying<br />
the H1N1 strain<br />
<br />
Their deaths take the total swine flu<br />
fatalities to 14, marking a sudden increase<br />
in the number of deaths since Glasgow<br />
mother Jacqui Fletcher became the UK's<br />
first swine flue victim in June.<br />
<br />
<div align=right>GlasGow Herold<br />
<div align=right>13 October 2009<br />
</div align=right><br />
</div align=right><br />
<br />
<br />
------<br />
In a <i>Wall Street Journal</i> article, [http://online.wsj.com/article/SB125832581224549493.html "These Hobbyists Add to Calculators, Multiplying Their Fun"], November 17, 2009, Dionne Searcey reports:<br />
<blockquote>After two months of trying to crack the code - a process that involved factoring two huge prime numbers - Mr. Moody says he succeeded in July.</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
In a <i>Psychology Today</i> article, [http://www.psychologytoday.com/blog/beautiful-minds/200905/interacting-women-makes-men-stupid “Interacting with women makes men stupid”], May 18, 2009, Scott Barry Kaufman reports about a Dutch research paper, [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJB-4W99W49-1&_user=10&_coverDate=05%2F15%2F2009&_rdoc=14&_fmt=high&_orig=browse&_srch=doc-info%28%23toc%236874%239999%23999999999%2399999%23FLA%23display%23Articles%29&_cdi=6874&_sort=d&_docanchor=&view=c&_ct=72&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=423a696535751f5ce6496af88f1514c1 “Interacting with women can impair men’s cognitive functioning”] (<i>Journal of Experimental Social Psychology</i>, May 2009). <br />
<br />
The article’s author reports:<br />
<blockquote>[M]ale participants tended to perform worse on a cognitive task …following the mixed-sex interaction compared to the same-sex interaction. …. Also, this effect was even stronger when the male participant reported higher attraction to the opposite-sex person they [<i>sic</i>] were interacting with. ….</blockquote><br />
<blockquote>It should be noted that there was evidence that women's cognitive performance did tend to decline after mixed-sex interactions if they reported having a relatively strong goal to impress the opposite-sex other.</blockquote> <br />
Another study result is reported:<br />
<blockquote>Part of boys' valuable cognitive resources may be spent on impressing their female class members.</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
----<br />
In an <i>Emax Health</i> article, [http://www.emaxhealth.com/1020/34/31485/cell-phone-ringtones-can-impair-retention.html “Cell Phone Ringtones Can Impair Retention”], June 3, 2009, Kathleen Blanchard reports about an LSU study of the effect of cell phone ringtones on short-term information retention. <br />
<blockquote>[P]eople exposed to cell phone ringtones had lower scores on tests after hearing ringtones in the classroom. ….<br><br />
[The researcher] said the familiar LSU fight song… ”slowed down their decision-making performance for a longer time than even a standard ringtone."</blockquote><br />
See also [http://news-info.wustl.edu/news/page/normal/14225.html “Cell phone ringtones can pose major distraction, impair recall”], by Gerry Everding, Washington University at St. Louis, May 28, 2009.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
From [http://online.wsj.com/article/SB10001424052748703735004574575880529756434.html “Why Changing the CEO May Not Change the Company”], by Jason Zweig, <i>The Wall Street Journal</i>, December 4, 2009<br />
<br />
<blockquote>If you took the CEOs with the best track records and brought them in to run the businesses with the worst performance, how often would those companies become more profitable? According to [an MIT] economist …, who has studied the effects of hundreds of management changes, the answer is roughly 60%. That isn't much better than the flip of a coin. ….<br><br />
<br />
The real force in corporate performance isn't the boss, but regression to the mean: Periods of good returns are highly likely to be followed by poor results, and vice versa.</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>“It’s only fifty-fifty you’ll get him back if you pay it,” he said factually …. I tried to smile. “Two to one, not bad odds at the track.”</blockquote><br />
<div align=right><i>The Man She Thought She Knew</i><br><br />
by Shari Shattuck, Pocket Books, 2006</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
==The value of negative data==<br />
<br />
[http://www.nytimes.com/2009/11/16/business/16records.html Little Benefit Seen, So Far, in Electronic Patient Records], Steve Lohr, The New York Times, November 15, 2009.<br />
<br />
[http://www.nytimes.com/2009/11/16/health/research/16heart.html Study Raises Questions About Cholesterol Drug’s Benefit], Natasha Singer, The New York Times, November 15, 2009.<br />
<br />
[http://www.nytimes.com/2009/11/15/business/15stream.html Seeking a Shorter Path to New Drugs], Steve Lohr, The New York Times, November 15, 2009.<br />
<br />
Negative data, data that disproves a commonly held belief about the superiority of a particular medical treatment, is especially valuable from an economic perspective, but doesn't get the respect it deserves.<br />
<br />
Providing high tech electronic health records should lead to better care, but apparently it doesn't.<br />
<br />
<blockquote>The nation is set to begin an ambitious program, backed by $19 billion in government incentives, to accelerate the adoption of computerized patient records in doctors’ offices and hospitals, replacing ink and paper. There is wide agreement that the conversion will bring better care and lower costs, saving the American health care system up to $100 billion a year by some estimates. But a new study comparing 3,000 hospitals at various stages in the adoption of computerized health records has found little difference in the cost and quality of care.</blockquote><br />
<br />
Previous studies had used a selected subset of health care practices.<br />
<br />
<blockquote>The study is an unusual effort to measure the impact of electronic health records nationally. Most of the evidence for gains from the technology, Dr. Jha said, has come from looking at an elite group of large, high-performing health providers that have spent years adapting their practices to the technology. The group usually includes Kaiser Permanente, the Mayo Clinic, the Cleveland Clinic and Intermountain Healthcare, among others.</blockquote><br />
<br />
In another study, an expensive cholesterol lowering drug was found to perform less well than a simple inexpensive alternative.<br />
<br />
<blockquote>For patients taking a statin to control high cholesterol, adding an old standby drug, niacin, was superior in reducing buildup in the carotid artery to adding Zetia, a newer drug that reduces bad cholesterol, according to a new study. The results of the study, published in The New England Journal of Medicine, were presented here Sunday night at an annual meeting of the American Heart Association.</blockquote><br />
<br />
The study was small (208 patients) and used a surrogate outcome, arterial wall thickness. The findings pitted raising good cholesterol against lowering bad cholesterol, and found that raising good cholesterol was better.<br />
<br />
<blockquote>Over the course of the 14-month study, the bad cholesterol of the patients on Zetia decreased by 19.2 percent, but the patients’ arterial wall thickness stayed the same, the study said. In the niacin group, good cholesterol increased by 18.4 percent and the carotid wall thickness decreased.</blockquote><br />
<br />
But the use of arterial wall thickness also led to criticism by Dr. Peter S. Kim, the president of Merck Research Laboratories who said that <br />
<br />
<blockquote>a drug’s ability to improve artery-wall thickness has not been proved to automatically correlate with a reduction in heart attacks.</blockquote><br />
<br />
The efficacy of Zetia has also been established on the basis of a surrogate outcome, reduction in levels of bad cholesterol.<br />
<br />
<blockquote>Zetia, he said, lowers bad cholesterol and lowering bad cholesterol is a known good. The study results “should be compared to the overwhelming body of evidence that lowering LDL cholesterol is an important thing to do to improve cardiovascular health,” Dr. Kim said.</blockquote><br />
<br />
Others, however, felt that this study showed problems with a heavily marketed drug.<br />
<br />
<blockquote>Some cardiologists here hailed the study as an indication that the popularity of Zetia and Vytorin, which had combined sales last year of about $4.6 billion, has far outstripped their evidence of a concrete benefit on heart health.</blockquote><br />
<br />
The final article noted the huge expense associated with drug development. Why does it cost $800 million to bring the average drug to market?<br />
<br />
<blockquote>Most of the cost in drug development is the price of failure, said Mervyn Turner, the chief strategy officer at the drug giant Merck. This linear, trial-and-error method is no longer a sustainable model for big pharmaceutical companies. “We invest far too long in bad ideas,” Dr. Turner said in a phone interview. “It is really important to stop that at an earlier stage in the cycle.”</blockquote><br />
<br />
One of the suggestions to reduce drug development cost is to publicize early failures.<br />
<br />
<blockquote>One idea is for drug makers to share information about compounds they have tried and shelved, for reasons like toxicity or inefficacy. Although many companies have committed to publishing the results of clinical trials, whether or not they succeed, drug makers don’t typically publish information about projects that fail at an earlier stage. A result is that companies waste many millions going down experimental paths that their competitors have already found to be dead ends. </blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Some people are trying to put a "spin" on the positive effects of electronic medical records at leading health care institutions and the lack of effect in a nationwide survey, as indicating that the electronic medical record works, but it takes time and effort. Do you agree or disagree?<br />
<br />
2. Zetia was approved by the FDA on the basis of a surrogate outcome, reduction in bad cholesterol, rather than in an outcome like decreased mortality or reduction in the number of heart attacks. Should the FDA require a new drug to show effectiveness on a direct measure instead of a surrogate measure?<br />
<br />
3. What are the barriers to drug companies sharing information about early failures in the drug development process?<br />
<br />
==Art for the birds==<br />
[http://esciencenews.com/articles/2009/06/30/a.birds.eye.view.art “A bird’s eye view of art”], <i>Science News</i>, June 30, 2009<br><br />
<br />
According to this very brief article, Japanese Professor Shigeru Watanabe has published a study in Springer’s <i>Animal Cognition</i>, which concludes:<br />
<blockquote>Pigeons could be art critics yet, ... like humans, pigeons can be trained to tell the difference between "good" and "bad" paintings.</blockquote><br />
Curious readers without access to this journal might be interested in an earlier, full-text online, Watanabe paper, [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1334394/pdf/jeabehav00221-0041.pdf “Pigeons’ Discrimination of Paintings by Monet and Picasso”] (<i>Journal of the Experimental Analysis of Behavior</i>, March 1995).<br />
<br />
<blockquote>Abstract: Pigeons successfully learned to discriminate color slides of paintings by Monet and Picasso. Following this training, they discriminated novel paintings by Monet and Picasso that had never been presented during the discrimination training. Furthermore, they showed generalization from Monet's to Cezanne's and Renoir's paintings or from Picasso's to Braque's and Matisse's paintings. These results suggest that pigeons' behavior can be controlled by complex visual stimuli in ways that suggest categorization. Upside-down images of Monet's paintings disrupted the discrimination, whereas inverted images of Picasso's did not. This result may indicate that the pigeons' behavior was controlled by objects depicted in impressionists'paintings but was not controlled by objects in cubists' paintings.</blockquote><br />
<br />
This paper describes in great detail (methodology, statistical test results) several controlled experiments on “eight experimentally naïve pigeons."<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Diversification of stock portfolios==<br />
[http://online.wsj.com/article/SB10001424052748704533904574548003614347452.html “More Stocks May Not Make a Portfolio Safer”]<br><br />
by Jason Zweig, <i>The Wall Street Journal</i>, November 26, 2009<br><br />
<br />
Conventional wisdom among financial planners is that investing in 10 up to 30 or 40 stocks provides adequate diversification for risk reduction. This "wisdom" is apparently backed up by studies. <br />
<blockquote>But this research on diversification was based on the average results of a large number of portfolios randomly generated by computer.</blockquote><br />
When LSU business professor Don Chance had his students build a portfolio of 30 stocks, one at a time, the results confirmed the conventional wisdom in that, after the first 20 stocks, portfolio risk, as measured by fluctuation in price, had been reduced by about 40% from that of the first stock alone.<br><br />
<br />
However, when Chance analyzed his individual students’ portfolios, he found that increasing the portfolio size from the first stock to the 30th resulted in 11% of the portfolios having more fluctuation than their first choice and 23% having more fluctuation than their first 5 choices.<br />
<blockquote>The lesson: For any given investor, the averages mightn't apply.</blockquote><br />
Chance found that his students had started their portfolios with a few brand-name companies with which they were familiar and soon ran out of familiar company names, subsequently picking stocks with much lower capitalization and thus more risk.<br> <br />
<br />
One financial planner commented:<br />
<blockquote>Humans can't think randomly …. Once people think of Exxon Mobil, they're a lot more likely to think of Chevron or another oil stock. For a lot of investors, diversification is like doing a word-association game.</blockquote><br />
Another planner commented:<br />
<blockquote>People who regard themselves as risk-averse will assemble portfolios of highly similar stocks that all seem to be "safe." The result, paradoxically, is a risky portfolio with every egg in one basket.</blockquote><br />
Chance also found that 13% of computer-generated 20-stock portfolios were riskier than one-stock portfolios.<br><br />
<br />
See [http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1485712 “Experimental Evidence on Portfolio Size and Diversification: Your Mileage May Vary”] to download a copy of the report.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==The remarkable story of Math's most contentious brain teaser.==<br />
The Monty Hall Problem<br />
Oxford Univerity Press, 2009<br><br />
Jason Douglace Rosenhouse<br />
<br />
Jason graduated from Dartmouth in 2000 and is currently Associate Professor of Mathematics, at James Madison University, Harrisonburg Virginia. His research has been in number theory but here he has written a book on the Monty Hall problem. <br />
<br />
Chapter 1 is called Ancestral Monty and includes among others a discussion of the Three Prisoners Paradox, Lets Make a Deal, and the Birth of the Monty Hall Problem. the Marylyn Vo Savant story that we all know about<br />
. <br />
<br />
Chapter 2 is called Classical Monte. And described as follows<br />
<br />
Version One: You are shown three identical doors. Behind one of them is a car. The other two conceal goats. You are asked to choose, but not open, one of the doors. After doing so, Monty, who knows where the car is, opens one of the two remaining doors. He always opens a door he knows to be incorrect, and randomly chooses which door to open when he has more than one option (Which happens on those occasions when your initial choice conceals the car). After opening an incorrect door, Monty gives you the choice of either switching to the unopened door or sticking with your original choice. You then receive what is in the door that you choose. What should you do? <br />
<br />
Chapter 3 is called Bayesian Monty <br />
<br />
Version Two: As before, Monty shows you three identical doors. One contains a car, the other two contain goats. You choose one of the doors but do not open it. This time, however, Monty does not know the location of the car. He randomly chooses one of the two doors different from your selection and opens it. The door turns out to conceal a goat. He now gives you the options either of sticking with your original door or switching to the other one. What should you do?<br />
<br />
Jason shows how to solve these two versions explaining the mathematics used in the two solutions.<br />
<br />
<br />
Chapter 4 is called Progressive Monty described as follows.<br />
<br />
This time we assume there are n identical doors, where n is an integer satisfying n >=3. One door conceals a car, the other n-1 conceal goats. You choose one of the doors at random but do not open it. Monty then opens a door he knows to conceal a goat, always choosing randomly always choosing randomly among the available doors. At this point he gives you the choice of sticking with your original door or switching to one of the remaining doors.<br />
<br />
You make your decision. Monty now eliminates another goat-concealing door (at random) and once more gives you the choice either of sticking or switching. This process continues until only two doors remain in play. What strategy should you follow to maximize your chances of winning?<br />
<br />
At the end of these chapters Jason writes:<br />
<br />
<blockquote>We have trodden a long and winding road to reach this point. We have navigated the rapids of the classical problem and some of the most natural variations. We confronted the full horror of the progressive version and emerged stronger for the experience. Along the way we have illuminated much of the world of probability theory and its offshoots. Yet for all of that, there remain certain variations on and aspects of the Monty Hall problem that have not fit comfortably into the preceding chapters. Our purpose now is to tie up some of these loose ends.</blockquote><br />
<br />
While the number 4 version is a horror the solution is amazingly simple. The optional strategy is to stick with your original door until only 2 doors remain and then switch, Your probability of winning for any n >= 4 is (n-1)/n.<br />
<br />
The proof is discussed in this book and also in<br />
<br />
Optimal strategies for progressive Monty Hall Problems<br> <br />
The Mathematical Gazette<br> <br />
Vol 93 No 528, Page 410<br><br />
November 2009<br><br />
Steven K. Lucas, Jason Rosenhouse<br><br />
<br />
You can find an earlier version by putting the title in google.<br />
<br />
Submitted by Laurie Snell<br />
<br />
==Simpson’s Paradox in the news==<br />
[http://online.wsj.com/article_email/SB125970744553071829-lMyQjAxMDI5NTA5MjcwMDI3Wj.html “When Combined Data Reveal the Flaw of Averages”]<br><br />
by Cari Tuna, <i>The Wall Street Journal</i>, December 2, 2009<br><br />
<br />
The subtitle of this article is “In a statistical Anomaly Dubbed Simpson’s Paradox, Aggregated Numbers Obscure Trends in Job Market, Medicine and Baseball.”<br><br />
<br />
The author reports about an anomaly which results from comparing unemployment rates for two periods, the early 1980s recession period and the current 2009 period. While unemployment rates are now lower for the population of all adult Americans, the rates for some subgroups of the population are higher.<br><br />
<blockquote>So how can the overall unemployment rate be lower today but higher among each group? The anomaly is an example of Simpson's Paradox -- a common but misleading statistical phenomenon rooted in the differing sizes of subgroups. Put simply, Simpson's Paradox reveals that aggregated data can appear to reverse important trends in the numbers being combined.</blockquote> <br />
The author discusses the well known example of Berkeley’s 1973 graduate admissions data, a 1986 study of kidney-stone treatments, and baseball statistics.<br />
<blockquote>[Harvard’s statistics chair] says he thinks many people who wield similarly misleading data do so unintentionally. "When you find data that go with your theory, then you don't dig deeper."</blockquote><br />
Bloggers [http://online.wsj.com/article_email/SB125970744553071829-lMyQjAxMDI5NTA5MjcwMDI3Wj.html#articleTabs%3Dcomments] mentioned additional examples of Simpson’s Paradox, on topics such as mean SAT scores compared over time, and infant mortality rates compared among different countries.<br> <br />
<br />
On the ISOSTAT listserv, readers were referred to Andrew Gelman’s comments on this article in [http://www.stat.columbia.edu/~cook/movabletype/archives/2009/12/simpsons_parado.html], posted on his website, Statistical Modeling, Causal Inference, and Social Science, December 3, 2009.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==STATS editor starts Forbes column==<br />
<br />
A recent STATS email announced that its editor, Trevor Butterworth, has debuted a weekly column, "Medialand," on <b><i>Forbes.com</i></b>. The focus appears to be on critiquing the coverage of scientific/statistical news by media folks.<br><br />
<br />
A click-able list of previous Butterworth columns [http://search.forbes.com/search/find?MT=forbes%20-%20butterworth] includes:<br />
<blockquote>“Can Plastic Change Your Sex?,” November 19, 2009<br><br />
“Tricked by Treats,” October 29, 2009</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
==Statistics make you stingy==<br />
<br />
Nicholas Kristof and Sheryl WuDunn have recently published "Half the Sky: Turning Oppression into Opportunity for Women Worldwide," a book about the global oppression of women, focusing on the sex slave trade, honor killings, rape as a wartime tactic, lack of maternal health care. Though they often cite statistics about the magnitude of these problems, they prefer to offer individual stories.<br />
<br />
About halfway through the book (page 99), they explain why.<br />
<br />
<blockquote>Frankly, we hesitate to pile on the data, since even when numbers are persuasive, they are not galvanizing. A growing collection of psychological studies show that statistics have a dulling effect, while it is individual stories that move people to act. In one experiment, research subjects were divided into several groups, and each person was asked to donate $5 to alleviate hunger abroad. One group was told the money would go to Rokia, a seven-year-old girl in Mali. Another group was told that the money would go to address malnutrition among 21 million Africans. The third group was told that the donations would go to Rokia, as in the first group, but this time her own hunger was presented as part of a background tapestry of global hunger, with some statistics thrown in. People were much more willing to donate to Rokia than to 21 million hungry people and even a mention of the larger problem made people less inclined to help her.</blockquote><br />
<br />
<blockquote>In another experiment, people were asked to donate to a $300,000 fund to fight cancer. One group was told that the money would be used to save the life of one child, while another group was told it would save the lives of eight children. People contributed almost twice as much to save one child as to save eight. Social psychologists argue that all this reflects the way our consciences and ethical systems are based on individual stories and are distinct from the part of our brains concerned with logic and rationality. Indeed, when subjects in experiments are first asked to solve math problems, thus putting in play the parts of the brain that govern logic, afterward they are less generous to the needy.</blockquote><br />
<br />
These thoughts bring to mind another famous (infamous?) quote by Joseph Stalin:<br />
<br />
<blockquote>A single death is a tragedy. A million deaths is a statistic.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Later in the book (page 141), Kristoff and WuDunn cite the need for "relentless empiricism" in developing policies for the prevention of AIDS. Is this a contradiction?<br />
<br />
2. Would you suspect that statisticians, as a group, are less generous than people in other professions?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Mammogram Math==<br />
[http://www.nytimes.com/2009/12/13/magazine/13Fob-wwln-t.html?_r=1&emc=tnt&tntemail1=y# New York Times], December 11 2009<br><br />
John Allen Paulos<br><br />
<br />
The U.S. Preventive Services Task Force (USPSTF) published a paper "Screening for Breast Cancer" in the ''Annals of Internal Medicine'' on November 17 2009 and recommended:<br />
<br />
(1) The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.<br />
<br />
(2) The USPSTF recommends biennial screening mammography for women aged 50 to 74 years.<br />
<br />
(3) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older<br />
<br />
These recommendations were changed on the December 15 2009 version to:<br />
<br />
(1) The USPSTF recommends biennial screening mammography for women aged 50 to 74 years.<br />
<br />
(2) The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.<br />
<br />
(3) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older.<br />
Since John's article was published on December 11 he must have used the first recommendations.<br />
<br />
John writes:<br />
<blockquote>Much of our discomfort with the panel's findings stems from a basic intuition: since earlier and more frequent screening increases the likelihood of detecting a possible fatal cancer, it is always desirable. But is this really so?</blockquote><br />
<br />
To understand why this is, John uses some expressions and words that we might not be familiar with. Here are two of these:<br />
''Reductio ad absurdum'' is a mode of argumentation that seeks to establish a contention by deriving an absurdity from its denial, thus arguing that a thesis must be accepted because its rejection would be untenable. It is a style of reasoning that has been employed throughout the history of mathematics and philosophy from classical antiquity onwards.<br />
<br />
In medicine, a disease is asymptomatic if a patient carries a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated.<br />
<br />
Then John writes:<br />
<br />
<blockquote> Applying it (''reductio ad absurdum'') to the contention that more screening is always better leads us to note that if screening catches the breast cancers of some asymptomatic women in their 40's then it would also catch those of some asymptomatic women in their 30's. But why stop there, why not monthly mammograms beginning at age 15? The answer, of course is that they would cause more harm than good.</blockquote> <br />
<br />
The rest of the article is devoted to the false positive paradox and a plea for the public to better understand probability and mathematics.<br />
<br />
The issues discussed here have occurred in other Chance News's. We encourage you to read the following<br />
<br />
Chance News 12 {http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_12#Screening Screening] <br />
<br />
Chance News 8 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Mammograms Validated as Key in Cancer Fight]<br />
<br />
Chance News 14<br />
[http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Calculated Risks Revisited]<br />
<br />
Submitted by Laurie Snell<br />
<br />
==N.F.L. Suspends Its Study on Concussions==<br />
[http://www.nytimes.com/2009/12/20/sports/football/20nfl.html?hpw New York Times, December 19,2009]<br><br />
Alan Schwarz<br />
<br />
The following quotations are from Linda T. Sanchez, Democrat of California, who complained (1) that the person doing the study of concussions of players was employed by the NFL and therefore suspect. Further, (2) she criticized the basis of comparison.<br />
<br />
<blockquote>Hey, why don't we let tobacco companies determine whether smoking is bad for your health or not?</blockquote><br />
<blockquote>That is sort of like comparing two-pack-a-day smokers with one-pack-a-day smokers to see what the differences are instead of two-pack-a-day smokers with the general population to see whether there is an increased risk of the activity that they are participating in to their health.</blockquote><br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_58&diff=9844Chance News 582009-12-20T18:25:47Z<p>PaulAlper: /* N.F.L. Suspends Its Study on Concussions */</p>
<hr />
<div>==Quotations==<br />
Berkeley law professor Kevin Quinn is working on a "statistical time machine" to compare Supreme Court justices' positions across historical time periods. He emailed Carl Bialik ([http://online.wsj.com/article/SB125789565331042445.html "Statistical Time Travel Helps Answer What-Ifs"], <i>The Wall Street Journal</i>, November 12, 2009) the following quotation:<br />
<blockquote>The famous statistician George Box once wrote that "all models are wrong, but some are useful."</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
Note: I encourage you to read the article by Carl Bialik (The numbers Guy) referred to above. JLS<br />
<br />
-----<br />
<blockquote>Everyone believes in the normal law, the experimenters because they imagine that it is a mathematical theorem, and the mathematicians because they think it is an experimental fact.</blockquote><br />
<div align=right>Gabriel Lippmann (French physicist)<br><br />
in Henri Poincaré's ''Calcul de probabilités'', 1896</div align=right><br />
Submitted by Steve Simon<br />
-----<br />
<blockquote>When times are good in financial markets, we’re willing to convince ourselves that they’re good for a reason. …. “When the trend is sideways to down, they think the machine is broken,” says [technical analyst] Robert Prechter. “Jeez, it can’t be us.” ....<br><br />
Prechter readily admits that he’s far from infallible. The standard, he says he wants to be held to is similar to that of a hitter in baseball, in which batting .300 makes one a star and.400 an immortal.</blockquote><br />
<br />
<div align=right>“Riding the Waves,” <i>TIME</i>, November 30, 2009</div align=right><br />
Submitted by Margaret Cibes<br />
-----<br />
<blockquote>From principles is derived probability, but truth or certainty is obtained only from facts.</blockquote> <br />
<br />
<div align=right>Tom Stoppard</div align=right><br />
Submitted by Laurie Snell<br><br />
<br />
==Forsooth== <br />
These Forsooths are from the December 2009 RSSNews.<br />
<br />
When to undertake surveys<br />
<br />
The ideal time for monitoring walking <br />
activity is when flows are highest, That is <br />
usually in June, and is linked to good <br />
weather and longer hours of daylight.<br />
However, because most walk journeys are<br />
for utility reasons, the number of walk<br />
journeys per month does not vary greatly <br />
- unlike cycling. School holidays influence<br />
walking patterns and the purpose of a <br />
trip is often time dependent.<br />
<br />
It is uncertain to what extent the weather<br />
influences the amount of walking activity <br />
overall. It is likely that leisure walking is <br />
more strongly affected by weather <br />
conditions than walking for utility <br />
purposes. <br />
<div align=right>Department for Transport website<br><br />
October 2009</div align=right><br />
-----<br />
40% rise in swine flu deaths in<br />
48 hours as two more die<br />
The number of swine flu deaths in Scotland has soared by 40% in just 48<br />
hours, after the Scottish Government<br />
Confirmed last night that a further two<br />
people died after contracting the virus.<br />
<br />
The patients, a 48-year-old man from<br />
Greater Glasgow and Clyde and an 81-<br />
year-old Fife woman, were both carrying<br />
the H1N1 strain<br />
<br />
Their deaths take the total swine flu<br />
fatalities to 14, marking a sudden increase<br />
in the number of deaths since Glasgow<br />
mother Jacqui Fletcher became the UK's<br />
first swine flue victim in June.<br />
<br />
<div align=right>GlasGow Herold<br />
<div align=right>13 October 2009<br />
</div align=right><br />
</div align=right><br />
<br />
<br />
------<br />
In a <i>Wall Street Journal</i> article, [http://online.wsj.com/article/SB125832581224549493.html "These Hobbyists Add to Calculators, Multiplying Their Fun"], November 17, 2009, Dionne Searcey reports:<br />
<blockquote>After two months of trying to crack the code - a process that involved factoring two huge prime numbers - Mr. Moody says he succeeded in July.</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
In a <i>Psychology Today</i> article, [http://www.psychologytoday.com/blog/beautiful-minds/200905/interacting-women-makes-men-stupid “Interacting with women makes men stupid”], May 18, 2009, Scott Barry Kaufman reports about a Dutch research paper, [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJB-4W99W49-1&_user=10&_coverDate=05%2F15%2F2009&_rdoc=14&_fmt=high&_orig=browse&_srch=doc-info%28%23toc%236874%239999%23999999999%2399999%23FLA%23display%23Articles%29&_cdi=6874&_sort=d&_docanchor=&view=c&_ct=72&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=423a696535751f5ce6496af88f1514c1 “Interacting with women can impair men’s cognitive functioning”] (<i>Journal of Experimental Social Psychology</i>, May 2009). <br />
<br />
The article’s author reports:<br />
<blockquote>[M]ale participants tended to perform worse on a cognitive task …following the mixed-sex interaction compared to the same-sex interaction. …. Also, this effect was even stronger when the male participant reported higher attraction to the opposite-sex person they [<i>sic</i>] were interacting with. ….</blockquote><br />
<blockquote>It should be noted that there was evidence that women's cognitive performance did tend to decline after mixed-sex interactions if they reported having a relatively strong goal to impress the opposite-sex other.</blockquote> <br />
Another study result is reported:<br />
<blockquote>Part of boys' valuable cognitive resources may be spent on impressing their female class members.</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
----<br />
In an <i>Emax Health</i> article, [http://www.emaxhealth.com/1020/34/31485/cell-phone-ringtones-can-impair-retention.html “Cell Phone Ringtones Can Impair Retention”], June 3, 2009, Kathleen Blanchard reports about an LSU study of the effect of cell phone ringtones on short-term information retention. <br />
<blockquote>[P]eople exposed to cell phone ringtones had lower scores on tests after hearing ringtones in the classroom. ….<br><br />
[The researcher] said the familiar LSU fight song… ”slowed down their decision-making performance for a longer time than even a standard ringtone."</blockquote><br />
See also [http://news-info.wustl.edu/news/page/normal/14225.html “Cell phone ringtones can pose major distraction, impair recall”], by Gerry Everding, Washington University at St. Louis, May 28, 2009.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
From [http://online.wsj.com/article/SB10001424052748703735004574575880529756434.html “Why Changing the CEO May Not Change the Company”], by Jason Zweig, <i>The Wall Street Journal</i>, December 4, 2009<br />
<br />
<blockquote>If you took the CEOs with the best track records and brought them in to run the businesses with the worst performance, how often would those companies become more profitable? According to [an MIT] economist …, who has studied the effects of hundreds of management changes, the answer is roughly 60%. That isn't much better than the flip of a coin. ….<br><br />
<br />
The real force in corporate performance isn't the boss, but regression to the mean: Periods of good returns are highly likely to be followed by poor results, and vice versa.</blockquote><br />
<br />
Submitted by Margaret Cibes<br />
<br />
-----<br />
<blockquote>“It’s only fifty-fifty you’ll get him back if you pay it,” he said factually …. I tried to smile. “Two to one, not bad odds at the track.”</blockquote><br />
<div align=right><i>The Man She Thought She Knew</i><br><br />
by Shari Shattuck, Pocket Books, 2006</div align=right><br />
Submitted by Margaret Cibes<br />
<br />
==The value of negative data==<br />
<br />
[http://www.nytimes.com/2009/11/16/business/16records.html Little Benefit Seen, So Far, in Electronic Patient Records], Steve Lohr, The New York Times, November 15, 2009.<br />
<br />
[http://www.nytimes.com/2009/11/16/health/research/16heart.html Study Raises Questions About Cholesterol Drug’s Benefit], Natasha Singer, The New York Times, November 15, 2009.<br />
<br />
[http://www.nytimes.com/2009/11/15/business/15stream.html Seeking a Shorter Path to New Drugs], Steve Lohr, The New York Times, November 15, 2009.<br />
<br />
Negative data, data that disproves a commonly held belief about the superiority of a particular medical treatment, is especially valuable from an economic perspective, but doesn't get the respect it deserves.<br />
<br />
Providing high tech electronic health records should lead to better care, but apparently it doesn't.<br />
<br />
<blockquote>The nation is set to begin an ambitious program, backed by $19 billion in government incentives, to accelerate the adoption of computerized patient records in doctors’ offices and hospitals, replacing ink and paper. There is wide agreement that the conversion will bring better care and lower costs, saving the American health care system up to $100 billion a year by some estimates. But a new study comparing 3,000 hospitals at various stages in the adoption of computerized health records has found little difference in the cost and quality of care.</blockquote><br />
<br />
Previous studies had used a selected subset of health care practices.<br />
<br />
<blockquote>The study is an unusual effort to measure the impact of electronic health records nationally. Most of the evidence for gains from the technology, Dr. Jha said, has come from looking at an elite group of large, high-performing health providers that have spent years adapting their practices to the technology. The group usually includes Kaiser Permanente, the Mayo Clinic, the Cleveland Clinic and Intermountain Healthcare, among others.</blockquote><br />
<br />
In another study, an expensive cholesterol lowering drug was found to perform less well than a simple inexpensive alternative.<br />
<br />
<blockquote>For patients taking a statin to control high cholesterol, adding an old standby drug, niacin, was superior in reducing buildup in the carotid artery to adding Zetia, a newer drug that reduces bad cholesterol, according to a new study. The results of the study, published in The New England Journal of Medicine, were presented here Sunday night at an annual meeting of the American Heart Association.</blockquote><br />
<br />
The study was small (208 patients) and used a surrogate outcome, arterial wall thickness. The findings pitted raising good cholesterol against lowering bad cholesterol, and found that raising good cholesterol was better.<br />
<br />
<blockquote>Over the course of the 14-month study, the bad cholesterol of the patients on Zetia decreased by 19.2 percent, but the patients’ arterial wall thickness stayed the same, the study said. In the niacin group, good cholesterol increased by 18.4 percent and the carotid wall thickness decreased.</blockquote><br />
<br />
But the use of arterial wall thickness also led to criticism by Dr. Peter S. Kim, the president of Merck Research Laboratories who said that <br />
<br />
<blockquote>a drug’s ability to improve artery-wall thickness has not been proved to automatically correlate with a reduction in heart attacks.</blockquote><br />
<br />
The efficacy of Zetia has also been established on the basis of a surrogate outcome, reduction in levels of bad cholesterol.<br />
<br />
<blockquote>Zetia, he said, lowers bad cholesterol and lowering bad cholesterol is a known good. The study results “should be compared to the overwhelming body of evidence that lowering LDL cholesterol is an important thing to do to improve cardiovascular health,” Dr. Kim said.</blockquote><br />
<br />
Others, however, felt that this study showed problems with a heavily marketed drug.<br />
<br />
<blockquote>Some cardiologists here hailed the study as an indication that the popularity of Zetia and Vytorin, which had combined sales last year of about $4.6 billion, has far outstripped their evidence of a concrete benefit on heart health.</blockquote><br />
<br />
The final article noted the huge expense associated with drug development. Why does it cost $800 million to bring the average drug to market?<br />
<br />
<blockquote>Most of the cost in drug development is the price of failure, said Mervyn Turner, the chief strategy officer at the drug giant Merck. This linear, trial-and-error method is no longer a sustainable model for big pharmaceutical companies. “We invest far too long in bad ideas,” Dr. Turner said in a phone interview. “It is really important to stop that at an earlier stage in the cycle.”</blockquote><br />
<br />
One of the suggestions to reduce drug development cost is to publicize early failures.<br />
<br />
<blockquote>One idea is for drug makers to share information about compounds they have tried and shelved, for reasons like toxicity or inefficacy. Although many companies have committed to publishing the results of clinical trials, whether or not they succeed, drug makers don’t typically publish information about projects that fail at an earlier stage. A result is that companies waste many millions going down experimental paths that their competitors have already found to be dead ends. </blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Some people are trying to put a "spin" on the positive effects of electronic medical records at leading health care institutions and the lack of effect in a nationwide survey, as indicating that the electronic medical record works, but it takes time and effort. Do you agree or disagree?<br />
<br />
2. Zetia was approved by the FDA on the basis of a surrogate outcome, reduction in bad cholesterol, rather than in an outcome like decreased mortality or reduction in the number of heart attacks. Should the FDA require a new drug to show effectiveness on a direct measure instead of a surrogate measure?<br />
<br />
3. What are the barriers to drug companies sharing information about early failures in the drug development process?<br />
<br />
==Art for the birds==<br />
[http://esciencenews.com/articles/2009/06/30/a.birds.eye.view.art “A bird’s eye view of art”], <i>Science News</i>, June 30, 2009<br><br />
<br />
According to this very brief article, Japanese Professor Shigeru Watanabe has published a study in Springer’s <i>Animal Cognition</i>, which concludes:<br />
<blockquote>Pigeons could be art critics yet, ... like humans, pigeons can be trained to tell the difference between "good" and "bad" paintings.</blockquote><br />
Curious readers without access to this journal might be interested in an earlier, full-text online, Watanabe paper, [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1334394/pdf/jeabehav00221-0041.pdf “Pigeons’ Discrimination of Paintings by Monet and Picasso”] (<i>Journal of the Experimental Analysis of Behavior</i>, March 1995).<br />
<br />
<blockquote>Abstract: Pigeons successfully learned to discriminate color slides of paintings by Monet and Picasso. Following this training, they discriminated novel paintings by Monet and Picasso that had never been presented during the discrimination training. Furthermore, they showed generalization from Monet's to Cezanne's and Renoir's paintings or from Picasso's to Braque's and Matisse's paintings. These results suggest that pigeons' behavior can be controlled by complex visual stimuli in ways that suggest categorization. Upside-down images of Monet's paintings disrupted the discrimination, whereas inverted images of Picasso's did not. This result may indicate that the pigeons' behavior was controlled by objects depicted in impressionists'paintings but was not controlled by objects in cubists' paintings.</blockquote><br />
<br />
This paper describes in great detail (methodology, statistical test results) several controlled experiments on “eight experimentally naïve pigeons."<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Diversification of stock portfolios==<br />
[http://online.wsj.com/article/SB10001424052748704533904574548003614347452.html “More Stocks May Not Make a Portfolio Safer”]<br><br />
by Jason Zweig, <i>The Wall Street Journal</i>, November 26, 2009<br><br />
<br />
Conventional wisdom among financial planners is that investing in 10 up to 30 or 40 stocks provides adequate diversification for risk reduction. This "wisdom" is apparently backed up by studies. <br />
<blockquote>But this research on diversification was based on the average results of a large number of portfolios randomly generated by computer.</blockquote><br />
When LSU business professor Don Chance had his students build a portfolio of 30 stocks, one at a time, the results confirmed the conventional wisdom in that, after the first 20 stocks, portfolio risk, as measured by fluctuation in price, had been reduced by about 40% from that of the first stock alone.<br><br />
<br />
However, when Chance analyzed his individual students’ portfolios, he found that increasing the portfolio size from the first stock to the 30th resulted in 11% of the portfolios having more fluctuation than their first choice and 23% having more fluctuation than their first 5 choices.<br />
<blockquote>The lesson: For any given investor, the averages mightn't apply.</blockquote><br />
Chance found that his students had started their portfolios with a few brand-name companies with which they were familiar and soon ran out of familiar company names, subsequently picking stocks with much lower capitalization and thus more risk.<br> <br />
<br />
One financial planner commented:<br />
<blockquote>Humans can't think randomly …. Once people think of Exxon Mobil, they're a lot more likely to think of Chevron or another oil stock. For a lot of investors, diversification is like doing a word-association game.</blockquote><br />
Another planner commented:<br />
<blockquote>People who regard themselves as risk-averse will assemble portfolios of highly similar stocks that all seem to be "safe." The result, paradoxically, is a risky portfolio with every egg in one basket.</blockquote><br />
Chance also found that 13% of computer-generated 20-stock portfolios were riskier than one-stock portfolios.<br><br />
<br />
See [http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1485712 “Experimental Evidence on Portfolio Size and Diversification: Your Mileage May Vary”] to download a copy of the report.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==The remarkable story of Math's most contentious brain teaser.==<br />
The Monty Hall Problem<br />
Oxford Univerity Press, 2009<br><br />
Jason Douglace Rosenhouse<br />
<br />
Jason graduated from Dartmouth in 2000 and is currently Associate Professor of Mathematics, at James Madison University, Harrisonburg Virginia. His research has been in number theory but here he has written a book on the Monty Hall problem. <br />
<br />
Chapter 1 is called Ancestral Monty and includes among others a discussion of the Three Prisoners Paradox, Lets Make a Deal, and the Birth of the Monty Hall Problem. the Marylyn Vo Savant story that we all know about<br />
. <br />
<br />
Chapter 2 is called Classical Monte. And described as follows<br />
<br />
Version One: You are shown three identical doors. Behind one of them is a car. The other two conceal goats. You are asked to choose, but not open, one of the doors. After doing so, Monty, who knows where the car is, opens one of the two remaining doors. He always opens a door he knows to be incorrect, and randomly chooses which door to open when he has more than one option (Which happens on those occasions when your initial choice conceals the car). After opening an incorrect door, Monty gives you the choice of either switching to the unopened door or sticking with your original choice. You then receive what is in the door that you choose. What should you do? <br />
<br />
Chapter 3 is called Bayesian Monty <br />
<br />
Version Two: As before, Monty shows you three identical doors. One contains a car, the other two contain goats. You choose one of the doors but do not open it. This time, however, Monty does not know the location of the car. He randomly chooses one of the two doors different from your selection and opens it. The door turns out to conceal a goat. He now gives you the options either of sticking with your original door or switching to the other one. What should you do?<br />
<br />
Jason shows how to solve these two versions explaining the mathematics used in the two solutions.<br />
<br />
<br />
Chapter 4 is called Progressive Monty described as follows.<br />
<br />
This time we assume there are n identical doors, where n is an integer satisfying n >=3. One door conceals a car, the other n-1 conceal goats. You choose one of the doors at random but do not open it. Monty then opens a door he knows to conceal a goat, always choosing randomly always choosing randomly among the available doors. At this point he gives you the choice of sticking with your original door or switching to one of the remaining doors.<br />
<br />
You make your decision. Monty now eliminates another goat-concealing door (at random) and once more gives you the choice either of sticking or switching. This process continues until only two doors remain in play. What strategy should you follow to maximize your chances of winning?<br />
<br />
At the end of these chapters Jason writes:<br />
<br />
<blockquote>We have trodden a long and winding road to reach this point. We have navigated the rapids of the classical problem and some of the most natural variations. We confronted the full horror of the progressive version and emerged stronger for the experience. Along the way we have illuminated much of the world of probability theory and its offshoots. Yet for all of that, there remain certain variations on and aspects of the Monty Hall problem that have not fit comfortably into the preceding chapters. Our purpose now is to tie up some of these loose ends.</blockquote><br />
<br />
While the number 4 version is a horror the solution is amazingly simple. The optional strategy is to stick with your original door until only 2 doors remain and then switch, Your probability of winning for any n >= 4 is (n-1)/n.<br />
<br />
The proof is discussed in this book and also in<br />
<br />
Optimal strategies for progressive Monty Hall Problems<br> <br />
The Mathematical Gazette<br> <br />
Vol 93 No 528, Page 410<br><br />
November 2009<br><br />
Steven K. Lucas, Jason Rosenhouse<br><br />
<br />
You can find an earlier version by putting the title in google.<br />
<br />
Submitted by Laurie Snell<br />
<br />
==Simpson’s Paradox in the news==<br />
[http://online.wsj.com/article_email/SB125970744553071829-lMyQjAxMDI5NTA5MjcwMDI3Wj.html “When Combined Data Reveal the Flaw of Averages”]<br><br />
by Cari Tuna, <i>The Wall Street Journal</i>, December 2, 2009<br><br />
<br />
The subtitle of this article is “In a statistical Anomaly Dubbed Simpson’s Paradox, Aggregated Numbers Obscure Trends in Job Market, Medicine and Baseball.”<br><br />
<br />
The author reports about an anomaly which results from comparing unemployment rates for two periods, the early 1980s recession period and the current 2009 period. While unemployment rates are now lower for the population of all adult Americans, the rates for some subgroups of the population are higher.<br><br />
<blockquote>So how can the overall unemployment rate be lower today but higher among each group? The anomaly is an example of Simpson's Paradox -- a common but misleading statistical phenomenon rooted in the differing sizes of subgroups. Put simply, Simpson's Paradox reveals that aggregated data can appear to reverse important trends in the numbers being combined.</blockquote> <br />
The author discusses the well known example of Berkeley’s 1973 graduate admissions data, a 1986 study of kidney-stone treatments, and baseball statistics.<br />
<blockquote>[Harvard’s statistics chair] says he thinks many people who wield similarly misleading data do so unintentionally. "When you find data that go with your theory, then you don't dig deeper."</blockquote><br />
Bloggers [http://online.wsj.com/article_email/SB125970744553071829-lMyQjAxMDI5NTA5MjcwMDI3Wj.html#articleTabs%3Dcomments] mentioned additional examples of Simpson’s Paradox, on topics such as mean SAT scores compared over time, and infant mortality rates compared among different countries.<br> <br />
<br />
On the ISOSTAT listserv, readers were referred to Andrew Gelman’s comments on this article in [http://www.stat.columbia.edu/~cook/movabletype/archives/2009/12/simpsons_parado.html], posted on his website, Statistical Modeling, Causal Inference, and Social Science, December 3, 2009.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==STATS editor starts Forbes column==<br />
<br />
A recent STATS email announced that its editor, Trevor Butterworth, has debuted a weekly column, "Medialand," on <b><i>Forbes.com</i></b>. The focus appears to be on critiquing the coverage of scientific/statistical news by media folks.<br><br />
<br />
A click-able list of previous Butterworth columns [http://search.forbes.com/search/find?MT=forbes%20-%20butterworth] includes:<br />
<blockquote>“Can Plastic Change Your Sex?,” November 19, 2009<br><br />
“Tricked by Treats,” October 29, 2009</blockquote><br />
Submitted by Margaret Cibes<br />
<br />
==Statistics make you stingy==<br />
<br />
Nicholas Kristof and Sheryl WuDunn have recently published "Half the Sky: Turning Oppression into Opportunity for Women Worldwide," a book about the global oppression of women, focusing on the sex slave trade, honor killings, rape as a wartime tactic, lack of maternal health care. Though they often cite statistics about the magnitude of these problems, they prefer to offer individual stories.<br />
<br />
About halfway through the book (page 99), they explain why.<br />
<br />
<blockquote>Frankly, we hesitate to pile on the data, since even when numbers are persuasive, they are not galvanizing. A growing collection of psychological studies show that statistics have a dulling effect, while it is individual stories that move people to act. In one experiment, research subjects were divided into several groups, and each person was asked to donate $5 to alleviate hunger abroad. One group was told the money would go to Rokia, a seven-year-old girl in Mali. Another group was told that the money would go to address malnutrition among 21 million Africans. The third group was told that the donations would go to Rokia, as in the first group, but this time her own hunger was presented as part of a background tapestry of global hunger, with some statistics thrown in. People were much more willing to donate to Rokia than to 21 million hungry people and even a mention of the larger problem made people less inclined to help her.</blockquote><br />
<br />
<blockquote>In another experiment, people were asked to donate to a $300,000 fund to fight cancer. One group was told that the money would be used to save the life of one child, while another group was told it would save the lives of eight children. People contributed almost twice as much to save one child as to save eight. Social psychologists argue that all this reflects the way our consciences and ethical systems are based on individual stories and are distinct from the part of our brains concerned with logic and rationality. Indeed, when subjects in experiments are first asked to solve math problems, thus putting in play the parts of the brain that govern logic, afterward they are less generous to the needy.</blockquote><br />
<br />
These thoughts bring to mind another famous (infamous?) quote by Joseph Stalin:<br />
<br />
<blockquote>A single death is a tragedy. A million deaths is a statistic.</blockquote><br />
<br />
===Questions===<br />
<br />
1. Later in the book (page 141), Kristoff and WuDunn cite the need for "relentless empiricism" in developing policies for the prevention of AIDS. Is this a contradiction?<br />
<br />
2. Would you suspect that statisticians, as a group, are less generous than people in other professions?<br />
<br />
Submitted by Steve Simon<br />
<br />
==Mammogram Math==<br />
[http://www.nytimes.com/2009/12/13/magazine/13Fob-wwln-t.html?_r=1&emc=tnt&tntemail1=y# New York Times], December 11 2009<br><br />
John Allen Paulos<br><br />
<br />
The U.S. Preventive Services Task Force (USPSTF) published a paper "Screening for Breast Cancer" in the ''Annals of Internal Medicine'' on November 17 2009 and recommended:<br />
<br />
(1) The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.<br />
<br />
(2) The USPSTF recommends biennial screening mammography for women aged 50 to 74 years.<br />
<br />
(3) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older<br />
<br />
These recommendations were changed on the December 15 2009 version to:<br />
<br />
(1) The USPSTF recommends biennial screening mammography for women aged 50 to 74 years.<br />
<br />
(2) The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.<br />
<br />
(3) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older.<br />
Since John's article was published on December 11 he must have used the first recommendations.<br />
<br />
John writes:<br />
<blockquote>Much of our discomfort with the panel's findings stems from a basic intuition: since earlier and more frequent screening increases the likelihood of detecting a possible fatal cancer, it is always desirable. But is this really so?</blockquote><br />
<br />
To understand why this is, John uses some expressions and words that we might not be familiar with. Here are two of these:<br />
''Reductio ad absurdum'' is a mode of argumentation that seeks to establish a contention by deriving an absurdity from its denial, thus arguing that a thesis must be accepted because its rejection would be untenable. It is a style of reasoning that has been employed throughout the history of mathematics and philosophy from classical antiquity onwards.<br />
<br />
In medicine, a disease is asymptomatic if a patient carries a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated.<br />
<br />
Then John writes:<br />
<br />
<blockquote> Applying it (''reductio ad absurdum'') to the contention that more screening is always better leads us to note that if screening catches the breast cancers of some asymptomatic women in their 40's then it would also catch those of some asymptomatic women in their 30's. But why stop there, why not monthly mammograms beginning at age 15? The answer, of course is that they would cause more harm than good.</blockquote> <br />
<br />
The rest of the article is devoted to the false positive paradox and a plea for the public to better understand probability and mathematics.<br />
<br />
The issues discussed here have occurred in other Chance News's. We encourage you to read the following<br />
<br />
Chance News 12 {http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_12#Screening Screening] <br />
<br />
Chance News 8 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_8#Mammograms_Validated_as_Key_in_Cancer_Fight Mammograms Validated as Key in Cancer Fight]<br />
<br />
Chance News 14<br />
[http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_14#Gerd_Gigerenzer.27s_Calculated_Risks_Revisited Calculated Risks Revisited]<br />
<br />
Submitted by Laurie Snell<br />
<br />
==N.F.L. Suspends Its Study on Concussions==<br />
[http://www.nytimes.com/2009/12/20/sports/football/20nfl.html?hpw New York Times, December 19,2009]<br><br />
Alan Schwarz<br />
<br />
The following quotations are from Linda T. Sanchez, Democrat of California, who complained (1) that the person doing the study of concussions of players was employed by the NFL and therefore suspect. Further, (2) she criticized the basis of comparison.<br />
<br />
<blockquote>Hey, why dont we let tobacco companies determine whether smoking is bad for your health or not?</blockquote><br />
<blockquote>That is sort of like comparing two-pack-a-day smokers with one-pack-a-day smokers to see what the differences are instead of two-pack-a-day smokers with the general population to see whether there is an increased risk of the activity that they are participating in to their health.</blockquote><br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_57&diff=9577Chance News 572009-10-30T22:41:43Z<p>PaulAlper: /* Vampirical */</p>
<hr />
<div>==Quotations==<br />
==Forsooths==<br />
<br />
==Vampirical==<br />
<br />
The following quotation can be found [http://www.stat.columbia.edu/~gelman/research/unpublished/power.pdf here] in an article by Gelman and Weakliem entitled, "Of beauty, sex and power: Statistical challenges in estimating small effects":<br />
<br />
<blockquote>This ability of the theory to explain findings in any direction is also pointed out by Freese (2007), who describes this sort of argument as "more 'vampirical' than 'empirical'--unable to be killed by mere evidence."</blockquote><br />
<br />
Gelman and Weakliem are criticizing research which putatively detects an effect merely because statistical significance is obtained on either side of zero or, in the case of ratio of females to males, 50%. In particular, they contest the results of studies which claim that “beautiful parents have more daughters, violent men have more sons and other sex-related patterns.” They also analyze so-called Type M (magnitude) errors and Type S (sign) errors.<br />
<br />
<blockquote>This is a Type M (magnitude) error: the study is constructed in such a way that any statistically-significant finding will almost certainly be a huge overestimate of the true effect. In addition there will be Type S (sign) errors, in which the estimate will be in the opposite direction as the true effect.</blockquote><br />
<br />
Discussion<br />
<br />
1. As a long-term research project, determine via literature and art how the notion of “beautiful” has changed through the ages and across cultures.<br />
<br />
2. The imbalance between baby daughters and baby sons produced by beautiful people somehow went from the original article’s (not statistically significant) 4.7% to 8% when dealing with the largest comparison (the most beautiful parents on a scale of 1 to 5) to 26% and finally to 36% via a typo in the New York Times. <br />
<br />
3. The authors, based on their analysis, say “There is no compelling evidence that “Beautiful parents produce more daughters.” Nevertheless, why did the original paper have so much appeal?<br />
<br />
4. As a check, the authors used People magazine’s “list of the fifty most beautiful people” from 1995 to 2000 to find the offsprings. There were “157 girls out of 329 children, or 47.7% girls (with a standard error 2.8%).” Instead of more females, fewer were produced.<br />
<br />
5. The authors note “the structure of scientific publication and media attention seem to have a biasing effect on social science research.” Explain what they mean by a “biasing effect.”<br />
<br />
Submitted by Paul Alper for Halloween.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_57&diff=9576Chance News 572009-10-30T20:41:33Z<p>PaulAlper: /* Vampirical */</p>
<hr />
<div>==Quotations==<br />
==Forsooths==<br />
<br />
==Vampirical==<br />
<br />
The following quotation can be found [http://www.stat.columbia.edu/~gelman/research/unpublished/power.pdf here] in an article by Gelman and Weakliem entitled, "Of beauty, sex and power: Statistical challenges in estimating small effects":<br />
<br />
This ability of the theory to explain findings in any direction is also pointed out by Freese (2007), who describes this sort of argument as "more 'vampirical' than 'empirical'--unable to be killed by mere evidence."<br />
<br />
Gelman and Weakliem are criticizing research which putatively detects an effect merely because statistical significance is obtained on either side of zero or, in the case of ratio of females to males, 50%. In particular, they contest the results of studies which claim that “beautiful parents have more daughters, violent men have more sons and other sex-related patterns.” They also analyze so-called Type M (magnitude) errors and Type S (sign) errors.<br />
<br />
"This is a Type M (magnitude) error: the study is constructed in such a way that any statistically-significant finding will almost certainly be a huge overestimate of the true effect. In addition there will be Type S (sign) errors, in which the estimate will be in the opposite direction as the true effect."<br />
<br />
Discussion<br />
<br />
1. As a long-term research project, determine via literature and art how the notion of “beautiful” has changed through the ages and across cultures.<br />
<br />
2. The imbalance between baby daughters and baby sons produced by beautiful people somehow went from the original article’s (not statistically significant) 4.7% to 8% when dealing with the largest comparison (the most beautiful parents on a scale of 1 to 5) to 26% and finally to 36% via a typo in the New York Times. <br />
<br />
3. The authors, based on their analysis, say “There is no compelling evidence that “Beautiful parents produce more daughters.” Nevertheless, why did the original paper have so much appeal?<br />
<br />
4. As a check, the authors used People magazine’s “list of the fifty most beautiful people” from 1995 to 2000 to find the offsprings. There were “157 girls out of 329 children, or 47.7% girls (with a standard error 2.8%).” Instead of more females, fewer were produced.<br />
<br />
5. The authors note “the structure of scientific publication and media attention seem to have a biasing effect on social science research.” Explain what they mean by a “biasing effect.”<br />
<br />
Submitted by Paul Alper for Halloween.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_56&diff=9536Chance News 562009-10-24T02:54:23Z<p>PaulAlper: /* Disc Fragments */</p>
<hr />
<div>==Quotations==<br />
<br />
<center><blockquote> I can calculate the motion of heavenly<br> bodies but not the madness of people</blockquote></center><br />
<br />
<div align="right">Isaac Newton<br><br />
After losing a fortune in the<br> South Sea Company bubble of 1720</div><br />
<br />
----<br />
<blockquote>Trying is the first step towards failure.</blockquote><br />
<div align=right>Homer Simpson</div align=right><br />
<br />
----<br />
At the website Language Log [http://languagelog.ldc.upenn.edu/nll/?p=1821#more-1821], Mark Liberman posted the following quotation from Miranda Robertson, in “Ockham’s broom,” a new series said to have been introduced on October 16, 2009, in the <i>Journal of Biology</i>:<br />
<blockquote>[I]t is probably safe to assume that most readers are familiar with Ockham’s razor – roughly, the principle whereby gratuitous suppositions are shaved from the interpretation of facts …. Ockham's broom is a somewhat more recent conceit, attributable to Sydney Brenner, and embodies the principle whereby inconvenient facts are swept under the carpet in the interests of a clear interpretation of a messy reality. (Or, some – possibly including Sydney Brenner – might say, in order to generate a publishable paper.)</blockquote><br />
<br />
----<br />
Jeff Witmer posted this quotation on the ISOSTAT listserv. It's Malcolm Gladwell's response [http://www.time.com/time/arts/article/0,8599,1931100,00.html?xid=rss-arts] to an interviewer, reported in <i>TIME</i>, October 20, 2009.<br />
<blockquote>If I was studying today, I would go get a master's in statistics, and maybe do a bunch of accounting courses and then write from that perspective. I think that's the way to survive. The role of the generalist is diminishing. Journalism has to get smarter.</blockquote><br />
<br />
== Forsooths==<br />
<br />
This forsooth is from the October 2009 RSS Forsooth. <br />
<br />
<blockquote>Of course in those days we worked on the assumption that everything was normally distributed and we have seen in the last few months that there is no such thing as a normal distribution. <br />
<div align="right">Scientific Computing World<br><br />
February/March 2009</div></blockquote><br />
<br />
You can see the context of this comment [http://www.scientific-computing.com/features/feature.php?feature_id=223 here].<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
<br />
According to a <i>New Yorker</i> (October 12, 2009) review [http://www.newyorker.com/arts/critics/atlarge/2009/10/12/091012crat_atlarge_lepore] of Matthew Stewart's <i>The Management Myth: Why the Experts Keep Getting It Wrong</i>, Stewart tells a story about how "his boss taught his twenty-something[-old] trainees ... how to conduct a 'two-handed regression'":<blockquote>"When a scatter plot failed to show the signifiant correlation between two variables that we all knew was there, he would place a pair of meaty hands over the offending clouds of data points and thereby reveal the straight line hiding from conventional mathematics." Management consulting isn't a science, Stewart says; it's a party trick.</blockquote><br />
<br />
==Minimizing the number of coins jingling in your pocket==<br />
<br />
[http://freakonomics.blogs.nytimes.com/2009/10/06/do-we-need-a-37-cent-coin/ Do We Need a 37-Cent Coin?] Steven d. Levitt, October 6, 2009, Freakonomics Blog, The New York Times.<br />
<br />
The current system of coins in the United States is inefficient. Patrick DeJarnette studied this problem and his work was highlighted in the Freakonomics blog. Dr. DeJarnette makes two assumptions.<br />
<br />
<blockquote>1. Some combination of coins must reach every integer value in [0,99].</blockquote><br />
<br />
<blockquote>2. Probability of a transaction resulting in value v is uniform from [0,99].</blockquote><br />
<br />
Under this system, the average number of coins that you would receive in change during a random transaction would be 4.7. The system that would work better is rather bizzarre.<br />
<br />
<blockquote>The most efficient systems? The penny, 3-cent piece, 11-cent piece, 37-cent piece, and (1,3,11,38) are tied at 4.10 coins per transaction.</blockquote><br />
<br />
Such a set of coins would be evocative of the [http://en.wikipedia.org/wiki/Harry_Potter_universe#Coins monetary system in the Harry Potter books].<br />
<br />
The article goes on to discuss systems where the coins are more conveniently priced and which single change in coins would lead to the greatest savings.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Minimizing the number of coins received in change is not the only criteria for a set of coin denominations. What other criteria make sense.<br />
<br />
2. Is it logical to assume a uniform distribution in this problem?<br />
<br />
3. What coin could be added to the current mix of coins to minimize the number of coins given in change.<br />
<br />
==Failure to disclose==<br />
[http://online.wsj.com/article/SB125511780864976689.html#articleTabs%3Darticle “Data Call Into Question HIV Study Results”]<br><br />
by Gautam Naik and Mark Schoofs, <i>The Wall Street Journal</i>, October 10, 2009<br><br />
<br />
Researchers from the U.S. Army and Thailand failed to disclose that some results of a potential HIV vaccine trial were not statistically significant, although they had this information when they announced the discovery.<br />
<br />
<blockquote>"We thought very hard about how to provide the clearest, most honest message," [one researcher] said. "We stand by the fact that this is a vaccine with a modest protective effect." He called the trial results "complex."</blockquote><br />
<br />
The first analysis, a “modified intent to treat” analysis, included “virtually everyone who enrolled in the study, regardless of whether they ended up getting the full course of the vaccine. …. By this measure, the vaccine tested in Thailand reduced by 31% the chance of infection with HIV ….”<br />
<br />
<blockquote>New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots. Statistical calculations showed there was a 3.9% probability that chance accounted for the difference. In drug and vaccine trials, anything above a 5% probability of a chance result is deemed statistically insignificant.</blockquote><br />
<br />
The second analysis, a “per protocol” analysis, included only the “study participants who got the full regimen of vaccine shots at the right time.” Apparently, for this group, in which 86 people were infected, there is a “16% chance the study results were a fluke.” It reduced by 26% the chance of infection with HIV.<br><br />
<br />
The article’s authors comment:<br />
<blockquote>It isn't clear why the vaccine was seemingly ineffective among participants who followed the guidelines to the letter.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
==More on AIDS Vaccine==<br />
<br />
“Hardly ever believe what you read” is a maxim that will stand you in good stead. Googling “aids vaccine Thailand” will get 248,000 hits, most of which are misleading. In essence, the URLs say that for the first time an effective vaccine against AIDS has been manufactured. But that was last month. Reality has now set in.<br />
<br />
The following chart found in [http://online.wsj.com/article/SB125511780864976689.html the Wall Street Journal of October 9, 2009] paints a different picture. “New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots.” Note that the “125” infections represent “51 + 74.”<br />
<br />
<br />
<center> http://www.dartmouth.edu/~chance/forwiki/HiV.gif</center><br />
<br />
The announcement on September 24, 2009 indicated that the p-value is 3.9%. A Minitab run shows that, in fact, the p-value is higher (i.e., worse) as indicated by the Fisher exact test. However, the .048 is still under the mystical .05:<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">51</div></td><br />
<td><div align="center">8197</div></td><br />
<td><div align="center">0.006222</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">74</div></td><br />
<td><div align="center">8198</div></td><br />
<td><div align="center">0.009027</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.00280480<br><br />
95% CI for difference: (-0.00546736, -0.000142249)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.06 P-Value = 0.039<br><br />
<br />
Fisher's exact test: P-Value = 0.048<br><br />
<br />
“Efficacy” of 31.2% seems to be determined from<br><br />
(74 - 51)/ 74 = .310<br><br />
<br />
In the final column of the chart--“Strictly adheres to trial design”--appears the unreleased<br> “per protocol” version. According to<br> [http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html Science Magazine]: <br />
<br />
::The second analysis is called “per protocol” and adheres strictly to how the trial was designed by only including the study participants who got the full regimen of vaccine shots at the right time. Because it excludes study participants who didn't get the full vaccine regimen, it usually provides corroboration to the looser “intent to treat” findings.<br />
<br />
The article doesn’t say what the breakdown of the 86 infections is. Nevertheless, it indicates that the p-value of 16% puts a damper on enthusiasm for the vaccine.<br />
<br />
::The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong.”<br />
<br />
Discussion<br />
<br />
1. “Strictly adheres to trial design” has an efficacy of 26.2% and 86 infections. Show that this leads approximately to 36 and 50 infections, respectively. <br />
<br />
2. The articles fail to tell us the number of participants in the “per protocol” situation. However, use the 36 and 50 cited above and show via a statistics package such as Minitab that the Fisher exact test comes up with about 16% for the p-value regardless of whether the sample sizes are the original ones or 4000 each, 5000 each, etc.<br />
<br />
3. The “researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin… The debate over the way the results were presented will have no immediate practical impact because even under the most optimistic assessment, the vaccine offered too little protection to be a serious candidate for widespread use.” If this is so, why was there so much positive publicity in September?<br />
<br />
Submitted by Paul Alper<br />
<br />
<br />
<br />
-----<br />
<br />
==Carrying a gun increases risk of getting shot and killed==<br />
[http://www.newscientist.com/article/dn17922-carrying-a-gun-increases-risk-of-getting-shot-and-killed.html The NewScientist]<Br> <br />
October 06 2009 <br><br />
Ewen Callaway<br />
<br />
In this article we read<br />
<blockquote>People who carry guns are far likelier to get shot – and killed – than those who are unarmed, a study of shooting victims in Philadelphia, Pennsylvania, has found. It would be impractical – not to say unethical – to randomly assign volunteers to carry a gun or not and see what happens. So Charles Branas's team at the University of Pennsylvania analyzed 677 shootings over two-and-a-half years to discover whether victims were carrying at the time, and compared them to other Philly residents of similar age, sex and ethnicity. The team also accounted for other potentially confounding differences, such as the socioeconomic status of their neighborhood.</blockquote><br />
Their article will appear in the American Journal of Public Health. The current version of this article can be found [http://www.ajph.org/cgi/reprint/AJPH.2008.143099v1.pdf here] and the most resent abstract can be found [http://www.ajph.org/cgi/content/abstract/AJPH.2008.143099v1 here] in this abstract we read:<br><br><br />
<blockquote>Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.<br><br><br />
Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.<br><br><br />
Results. After adjustment, individuals in possession of a gun were 4.46 (P<.05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P<.05).<br><br><br />
Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.</blockquote><br />
<br />
Discussion<br />
<br />
Why do you think the New Science and other's discussing this study titled there article "Carrying a gun increases risk of getting shot and killed" rather than the title of of the article "Investigating the Link Between Gun Possession and Gun Assault"?<br />
<br />
Of course this is the kind of article that lends iself to interesting comments. For example:<br />
<br />
I am definitely going to have to find the complete article. I want to see how they determined which victims of being shot were included in the study and how they determined which civilians would be included in the study. With out that information, this study doesn't really mean anything.<br />
<br />
Follow this advice and see if you think the study really means anything.<br />
<br />
Sounds to me like a completely ignorant study and weighted to get the result they want. If you check a place like Philidelphia, of course this is the result you would get, because the people carrying guns are more likely to be involved in crimes or living in crime ridden areas. Check Dallas, or Oklahoma City. You wouldn't get that result at all. And that's because dang near everybody has guns, and we have far fewer shootings.<br />
<br />
Does this suggest that the study is completely ignorant?<br />
<br />
This article was suggested by Gordon Fox<br />
<br />
==Identifying financial market cycles - or not==<br />
[http://www.newyorker.com/reporting/2009/10/12/091012fa_fact_paumgarten “The Secret Cycle”], by Nick Paumgarten, <i>The New Yorker</i>, October 12, 2009<br><br />
<br />
This article focuses on the work of Martin Armstrong, a technical financial analyst, who found that, "on average, there had been a panic every 8.6 years" over the period 1683-1907:<br />
<blockquote>He discerned a recurrence of major turning points in the economy and in world affairs that followed a distinct and unwavering 8.6-year rhythm.</blockquote><br />
<br />
Then he found that the October 1987 crash “took place on the minor halfway point up the first leg of the 8.6-year cycle, at 2.15 years,” noting that "8.6 years was exactly … 3,141 [days], the number pi times a thousand.”<br><br />
<br />
Eventually:<br />
<blockquote>The model … failed, among other things, to foresee its developer’s demise. In September, 1999, Armstrong was charged with defrauding Japanese investors of nearly a billion dollars. …. The upshot, though, is that he has now spent more than nine years in jail – a pi cycle and then some.</blockquote><br />
<br />
The article includes discussions of Fibonacci-based market behavior models and the "reasoning" behind them.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Learning by the petabyte==<br />
<br />
[http://www.nytimes.com/2009/10/12/technology/12data.html Training to Climb an Everest of Digital Data]. Ashlee Vance, The New York Times, October 11, 2009.<br />
<br />
Some Statistics textbooks have been criticized for having small "toy" problems that do not reflect the complexity of data analysis out in the real world. What sort of data sets are out in the real world?<br />
<br />
<blockquote> Facebook, for example, uses more than 1 petabyte of storage space to manage its users’ 40 billion photos. It was not long ago that the notion of one company having anything close to 40 billion photos would have seemed tough to fathom. Google, meanwhile, churns through 20 times that amount of information every single day just running data analysis jobs. In short order, DNA sequencing systems too will generate many petabytes of information a year.</blockquote><br />
<br />
Even at the best universities, students are not asked to handle data sets this large. And this is a problem.<br />
<br />
<blockquote>For the most part, university students have used rather modest computing systems to support their studies. They are learning to collect and manipulate information on personal computers or what are known as clusters, where computer servers are cabled together to form a larger computer. But even these machines fail to churn through enough data to really challenge and train a young mind meant to ponder the mega-scale problems of tomorrow. "If they imprint on these small systems, that becomes their frame of reference and what they’re always thinking about," said Jim Spohrer, a director at I.B.M.'s Almaden Research Center. </blockquote><br />
<br />
Two companies with lots of experience tackling petabyte sized data sets want to change this.<br />
<br />
<blockquote>Two years ago, I.B.M. and Google set out to change the mindset at universities by giving students broad access to some of the largest computers on the planet. The companies then outfitted the computers with software that Internet companies use to tackle their toughest data analysis jobs. And, rather than building a big computer at each university, the companies created a system that let students and researchers tap into giant computers over the Internet. This year, the National Science Foundation, a federal government agency, issued a vote of confidence for the project by splitting $5 million among 14 universities that want to teach their students how to grapple with big data questions.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. What is the size of the largest data set that you have ever analyzed. Did the size of the data set force you to use a different computing system, different software, or a different statistical method?<br />
<br />
2. Could a random sample of a few megabytes from a petabyte of data be sufficiently useful to learn on? Note that a megabyte is six orders of magnitude smaller than a petabyte. Is it possible to have a representative sample with a data set sampled this sparsely?<br />
<br />
3. [http://en.wikipedia.org/wiki/Moore%27s_law Moore's Law] says (more or less) that computing capacity doubles every two years (some sources say 18 months). If Moore's Law applies, calculate how long will it take before we see petabyte sized hard drives on laptop computers?<br />
<br />
==The unluckiest fan==<br />
[http://www.npr.org/templates/story/story.php?storyId=113884165 Nats follower may be unluckiest fan]<br><br />
All Things Considered, NPR, 16 October 2009.<br />
<br />
The Washington Nationals baseball team posted a dismal won-lost record of 59-103 for the 2009 season. From the link above, you can listen to an interview with season-ticket holder Stephen Krupin, who watched the team lose all 19 games he attended this year. The host speculates that this must be a record for bad luck. In fact, Mr. Krupin reports that his cousin, a PhD economist, calculated the chance that this would happen as 1 in 131,204. <br />
<br />
In comments posted on the NPR site, several listeners attempt to reproduce this calculation, but find that the event appears to be more likely than reported. It turns out that their analyses are based on the full season record--which seems natural since that record is featured so prominently in the story. However, it comes out in the interview that Mr. Krupin attended only home games. From the [http://mlb.mlb.com/mlb/standings/ Major League Baseball standings] we see that the Nationals were 33–48 at home and 26–55 on the road. The chance that 19 randomly selected home games are all losses is <math>{48 \choose 19}/ {81 \choose 19} </math>, which equals 1 in 131203.8, in agreement with Mr. Krupin's report.<br />
<br />
We had another curious experience trying to get the data to match the calculation. An initial try found a [http://washington.nationals.mlb.com/schedule/sortable.jsp?c_id=was&year=2009 sortable schedule] on the Washington Nationals web site. Selecting the home games produces 85 entries: 34 wins, 48 losses and 3 postponements. Baseball fans will recognize that 34 plus 48 gives one too many home games, but how do we account for the extra win? It turns out that the May 5 game against the Astros was [http://www.usatoday.com/sports/baseball/2009-05-05-nats-astros-gamer_N.htm suspended by rain in the 11th inning], with the score tied 10-10. The game was completed on July 9, with the Nationals ultimately winning 11-10. This result appears twice in the schedule, once on each date. <br />
<br />
Submitted by Bill Peterson, based on a suggestion from Jeanne Albert.<br />
<br />
==More on who's happier==<br />
[http://languagelog.ldc.upenn.edu/nll/?p=1753 “The Happiness Gap is back is back is back is back”]<br><br />
by Mark Liberman, Language Log (online blog), September 20, 2009<br><br />
<br />
This is an update of Liberman's 2007 Language Log blog [http://itre.cis.upenn.edu/~myl/languagelog/archives/004965.html “The ‘Happiness Gap’ and the Rhetoric of Statistics”], which was posted in reaction to David Leonhardt’s 2007 <i>New York Times</i> article [http://www.nytimes.com/2007/09/26/business/26leonhardt.html?ex=1348545600&en=594e67d014f6dc88&ei=5124&partner=permalink&exprod=permalink “He’s Happier, She’s Less So”].<br><br />
<br />
He writes now in reaction to recently updated data and to the renewed spate of 2009 articles on this topic:<br> <br />
(a) NYT’s Ross Douthat in [http://www.nytimes.com/2009/05/26/opinion/26douthat.html?_r=1 “Liberated and Unhappy”]<br> <br />
(b) Huffington Post’s [http://www.huffingtonpost.com/arianna-huffington/the-sad-shocking-truth-ab_b_290021.html “The Sad, Shocking Truth About How Women Are Feeling”], [http://www.huffingtonpost.com/marcus-buckingham/whats-happening-to-womens_b_289511.html “What’s Happening To Women’s Happiness?”], <i>etc.</i><br> <br />
(c) NYT’s Marueen Dowd in [http://www.nytimes.com/2009/09/20/opinion/20dowd.html “Blue Is the New Black”].<br><br />
<br />
Here are the original and updated percents:<br><br />
<br />
1972-74<br> <br />
Men 31.9 very happy, 53.0 pretty happy, 15.1 not too happy<br><br />
Women 37.0 very happy, 49.4 pretty happy, 13.6 not too happy<br><br />
<br />
2004-08<br> <br />
Men 29.8 very happy, 56.1 pretty happy, 14.0 not too happy<br><br />
Women 31.2 very happy, 54.9 pretty happy, 13.9 not too happy<br><br />
<br />
Liberman refers readers to his more detailed 2007 discussion of the statistical issues – sample size, self-reporting, statistical vs. practical significance – including references to lots of other articles related to these survey results, in [http://itre.cis.upenn.edu/~myl/languagelog/archives/004987.html “The ‘Gender Happiness Gap’: Statistical, practical and rhetorical Significance”].<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Disc Fragments==<br />
<br />
The dream of every clinical trial is to come up with something which is inexpensive, definitive and likely to result in media publicity. “Improved outcome after lumbar microdiscectomy in patients shown their excised disc fragments: a prospective, double blind, randomized, controlled trial” by M.J. Tait, et al [http://www.ncbi.nlm.nih.gov/pubmed/19684238 here] fulfills the desire. <br />
<br />
According to local Twin Cities website with the heading, [http://www.minnpost.com/healthblog/2009/09/03/11307/seeing_it_appears_is_believing_when_it_comes_to_back_surgery Seeing, it appears, is believing when it comes to back surgery]: “British surgeons report that patients who underwent a surgical procedure (lumbar microdiscectomy) for back pain caused by a spinal disc tear (“slipped disc”) had better outcomes when they received fragments of their removed disc after the operation. That’s right. Simply taking home a souvenir of the operation in a pot of saline solution improved the patients’ recovery. They reported less leg and back pain, less leg weakness and less “pins and needles” sensations (paresthesia). They also took fewer pain medications after the surgery.”<br />
<br />
The surgeons “said they decided to do the study for two main reasons: They knew that a patient’s anxiety and depression going into surgery for a spinal disc tear has a big impact on the recovery process. They had also noticed, anecdotally, that many of their patients who responded best to the surgery — and who seemed to experience the least anxiety and depression afterwards — were those who had been given their disc fragments.”<br />
<br />
The abstract of the journal article notes low p-values to make their case “that presenting the removed disc material to patients after LMD improves patient outcome.”:<br />
<br />
<blockquote>Lumbar microdiscectomy (LMD) is a commonly performed neurosurgical procedure. We set up a prospective, double blind, randomised, controlled trial to test the hypothesis that presenting the removed disc material to patients after LMD improves patient outcome. METHODS: Adult patients undergoing LMD for radiculopathy caused by a prolapsed intervertebral disc were randomised into one of two groups, termed experimental and control. Patients in the experimental group were given their removed disc fragments whereas patients in the control group were not. Patients were unaware of the trial hypothesis and investigators were blinded to patient group allocation. Outcome was assessed between 3 and 6 months after LMD. Primary outcome measures were the degree of improvement in sciatica and back pain reported by the patients. Secondary outcome measures were the degree of improvement in leg weakness, paraesthesia, numbness, walking distance and use of analgesia reported by the patients. RESULTS: Data from 38 patients in the experimental group and 36 patients in the control groSummaryup were analysed. The two groups were matched for age, sex and preoperative symptoms. More patients in the experimental compared with the control group reported improvements in leg pain (91.5 vs 80.4%; p<0.05), back pain (86.1 vs 75.0%; p<0.05), limb weakness (90.5 vs 56.3%; p<0.02), paraesthesia (88 vs 61.9%; p<0.05) and reduced analgesic use (92.1 vs 69.4%; p<0.02) than preoperatively. CONCLUSION: Presentation of excised disc fragments is a cheap and effective way to improve outcome after LMD.</blockquote><br />
<br />
The entire paper is only three pages in length and so its calculations can be checked. Below are the calculation results for the three secondary outcomes for which the paper claims statistical significance:<br />
<br />
1. Improved Leg Weakness--the paper states that the p-value is less that .02. Minitab shows that the p-Fisher’s exact test is .024<br />
<br />
'''T and CI for Two Proportions''' [leg weakness]<br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">9</div></td><br />
<td><div align="center">16</div></td><br />
<td><div align="center">0.562500</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">19</div></td><br />
<td><div align="center">21</div></td><br />
<td><div align="center">0.904762</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.342262<br><br />
95% CI for difference: (-0.615844, -0.0686795)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.45 P-Value = 0.014<br />
<br />
Fisher's exact test: P-Value = 0.024<br />
<br />
2. Parathaesia--The paper states that the p-value is less that .05. Minitab shows that the p-value is from Fisher’s exact test is .08.<br />
<br />
Test and CI for Two Proportions [parathaesia]<br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">22</div></td><br />
<td><div align="center">25</div></td><br />
<td><div align="center">0.880000</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">13</div></td><br />
<td><div align="center">21</div></td><br />
<td><div align="center">0.619048</div></td><br />
</tr><br />
</table><br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.260952<br><br />
95% CI for difference: (0.0173021, 0.504603)<br><br />
Test for difference = 0 (vs not = 0): Z = 2.10 P-Value = 0.036<br />
<br />
Fisher's exact test: P-Value = 0.080<br />
<br />
3. Reduced Analgesic Use--The paper states that the p-value is less that .02. Minitab shows that the p-value from Fisher’s exact test is .017.<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">35</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">o.921053</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">25</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.694444</div></td><br />
</tr><br />
</table><br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.226608<br><br />
95% CI for difference: (0.0534229, 0.399793)<br><br />
Test for difference = 0 (vs not = 0): Z = 2.49 P-Value = 0.013<br />
<br />
Fisher's exact test: P-Value = 0.017<br />
<br />
The primary outcomes, leg pain and (low) back pain for the treatment vs. the control were not calculated in a similar manner to the way the secondary outcomes were. Instead of using a two-sample test of proportions, the results for “pain” were calculated by having five categories: “Much better,” Little better,” “Same,” “Little worse,” and “Much worse.” That is, an ordinal scale was employed. Because the accompanying graphs, Figure 1A and 1B in the paper, are not precise enough to determine the number in each category, a nonparametric calculation is hard to carry out.<br />
<br />
Nevertheless, ignoring the breakdown into five categories, here are Minitab results for leg pain and back pain, respectively; note that the p-values are much different from the claimed <.05:<br />
<br />
Test and CI for Two Proportions [leg pain]<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">35</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.921053</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">29</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.805556</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.115497<br><br />
95% CI for difference: (-0.0396318, 0.270626)<br><br />
Test for difference = 0 (vs not = 0): Z = 1.46 P-Value = 0.144<br />
<br />
Fisher's exact test: P-Value = 0.185<br />
<br />
Test and CI for Two Proportions [back pain]<br />
Sample X N Sample p <br />
1 33 38 0.868421<br />
2 27 36 0.750000<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">33</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.868421</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">27</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.750000</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.118421<br><br />
95% CI for difference: (-0.0592271, 0.296069)<br><br />
Test for difference = 0 (vs not = 0): Z = 1.31 P-Value = 0.191<br />
<br />
Fisher's exact test: P-Value = 0.242 <br />
<br />
Discussion<br />
<br />
1. Why might an individual report a better outcome because he was handed his disc fragment? Why might he feel worse?<br />
<br />
2. Assuming that the p-values reported in the article are correct, what criticism might still remain?<br />
<br />
3. A disc fragment is one form of excised body part. What other excised body part might have a similar positive result? What other excise body part might have a distinctly negative result?<br />
<br />
4. This study took place in London, England. Why might patient reaction be different in, let us say, Asia or Africa?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_56&diff=9493Chance News 562009-10-24T02:52:51Z<p>PaulAlper: /* Disc Fragments */</p>
<hr />
<div>==Quotations==<br />
<br />
<center><blockquote> I can calculate the motion of heavenly<br> bodies but not the madness of people</blockquote></center><br />
<br />
<div align="right">Isaac Newton<br><br />
After losing a fortune in the<br> South Sea Company bubble of 1720</div><br />
<br />
----<br />
<blockquote>Trying is the first step towards failure.</blockquote><br />
<div align=right>Homer Simpson</div align=right><br />
<br />
----<br />
At the website Language Log [http://languagelog.ldc.upenn.edu/nll/?p=1821#more-1821], Mark Liberman posted the following quotation from Miranda Robertson, in “Ockham’s broom,” a new series said to have been introduced on October 16, 2009, in the <i>Journal of Biology</i>:<br />
<blockquote>[I]t is probably safe to assume that most readers are familiar with Ockham’s razor – roughly, the principle whereby gratuitous suppositions are shaved from the interpretation of facts …. Ockham's broom is a somewhat more recent conceit, attributable to Sydney Brenner, and embodies the principle whereby inconvenient facts are swept under the carpet in the interests of a clear interpretation of a messy reality. (Or, some – possibly including Sydney Brenner – might say, in order to generate a publishable paper.)</blockquote><br />
<br />
----<br />
Jeff Witmer posted this quotation on the ISOSTAT listserv. It's Malcolm Gladwell's response [http://www.time.com/time/arts/article/0,8599,1931100,00.html?xid=rss-arts] to an interviewer, reported in <i>TIME</i>, October 20, 2009.<br />
<blockquote>If I was studying today, I would go get a master's in statistics, and maybe do a bunch of accounting courses and then write from that perspective. I think that's the way to survive. The role of the generalist is diminishing. Journalism has to get smarter.</blockquote><br />
<br />
== Forsooths==<br />
<br />
This forsooth is from the October 2009 RSS Forsooth. <br />
<br />
<blockquote>Of course in those days we worked on the assumption that everything was normally distributed and we have seen in the last few months that there is no such thing as a normal distribution. <br />
<div align="right">Scientific Computing World<br><br />
February/March 2009</div></blockquote><br />
<br />
You can see the context of this comment [http://www.scientific-computing.com/features/feature.php?feature_id=223 here].<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
<br />
According to a <i>New Yorker</i> (October 12, 2009) review [http://www.newyorker.com/arts/critics/atlarge/2009/10/12/091012crat_atlarge_lepore] of Matthew Stewart's <i>The Management Myth: Why the Experts Keep Getting It Wrong</i>, Stewart tells a story about how "his boss taught his twenty-something[-old] trainees ... how to conduct a 'two-handed regression'":<blockquote>"When a scatter plot failed to show the signifiant correlation between two variables that we all knew was there, he would place a pair of meaty hands over the offending clouds of data points and thereby reveal the straight line hiding from conventional mathematics." Management consulting isn't a science, Stewart says; it's a party trick.</blockquote><br />
<br />
==Minimizing the number of coins jingling in your pocket==<br />
<br />
[http://freakonomics.blogs.nytimes.com/2009/10/06/do-we-need-a-37-cent-coin/ Do We Need a 37-Cent Coin?] Steven d. Levitt, October 6, 2009, Freakonomics Blog, The New York Times.<br />
<br />
The current system of coins in the United States is inefficient. Patrick DeJarnette studied this problem and his work was highlighted in the Freakonomics blog. Dr. DeJarnette makes two assumptions.<br />
<br />
<blockquote>1. Some combination of coins must reach every integer value in [0,99].</blockquote><br />
<br />
<blockquote>2. Probability of a transaction resulting in value v is uniform from [0,99].</blockquote><br />
<br />
Under this system, the average number of coins that you would receive in change during a random transaction would be 4.7. The system that would work better is rather bizzarre.<br />
<br />
<blockquote>The most efficient systems? The penny, 3-cent piece, 11-cent piece, 37-cent piece, and (1,3,11,38) are tied at 4.10 coins per transaction.</blockquote><br />
<br />
Such a set of coins would be evocative of the [http://en.wikipedia.org/wiki/Harry_Potter_universe#Coins monetary system in the Harry Potter books].<br />
<br />
The article goes on to discuss systems where the coins are more conveniently priced and which single change in coins would lead to the greatest savings.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Minimizing the number of coins received in change is not the only criteria for a set of coin denominations. What other criteria make sense.<br />
<br />
2. Is it logical to assume a uniform distribution in this problem?<br />
<br />
3. What coin could be added to the current mix of coins to minimize the number of coins given in change.<br />
<br />
==Failure to disclose==<br />
[http://online.wsj.com/article/SB125511780864976689.html#articleTabs%3Darticle “Data Call Into Question HIV Study Results”]<br><br />
by Gautam Naik and Mark Schoofs, <i>The Wall Street Journal</i>, October 10, 2009<br><br />
<br />
Researchers from the U.S. Army and Thailand failed to disclose that some results of a potential HIV vaccine trial were not statistically significant, although they had this information when they announced the discovery.<br />
<br />
<blockquote>"We thought very hard about how to provide the clearest, most honest message," [one researcher] said. "We stand by the fact that this is a vaccine with a modest protective effect." He called the trial results "complex."</blockquote><br />
<br />
The first analysis, a “modified intent to treat” analysis, included “virtually everyone who enrolled in the study, regardless of whether they ended up getting the full course of the vaccine. …. By this measure, the vaccine tested in Thailand reduced by 31% the chance of infection with HIV ….”<br />
<br />
<blockquote>New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots. Statistical calculations showed there was a 3.9% probability that chance accounted for the difference. In drug and vaccine trials, anything above a 5% probability of a chance result is deemed statistically insignificant.</blockquote><br />
<br />
The second analysis, a “per protocol” analysis, included only the “study participants who got the full regimen of vaccine shots at the right time.” Apparently, for this group, in which 86 people were infected, there is a “16% chance the study results were a fluke.” It reduced by 26% the chance of infection with HIV.<br><br />
<br />
The article’s authors comment:<br />
<blockquote>It isn't clear why the vaccine was seemingly ineffective among participants who followed the guidelines to the letter.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
==More on AIDS Vaccine==<br />
<br />
“Hardly ever believe what you read” is a maxim that will stand you in good stead. Googling “aids vaccine Thailand” will get 248,000 hits, most of which are misleading. In essence, the URLs say that for the first time an effective vaccine against AIDS has been manufactured. But that was last month. Reality has now set in.<br />
<br />
The following chart found in [http://online.wsj.com/article/SB125511780864976689.html the Wall Street Journal of October 9, 2009] paints a different picture. “New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots.” Note that the “125” infections represent “51 + 74.”<br />
<br />
<br />
<center> http://www.dartmouth.edu/~chance/forwiki/HiV.gif</center><br />
<br />
The announcement on September 24, 2009 indicated that the p-value is 3.9%. A Minitab run shows that, in fact, the p-value is higher (i.e., worse) as indicated by the Fisher exact test. However, the .048 is still under the mystical .05:<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">51</div></td><br />
<td><div align="center">8197</div></td><br />
<td><div align="center">0.006222</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">74</div></td><br />
<td><div align="center">8198</div></td><br />
<td><div align="center">0.009027</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.00280480<br><br />
95% CI for difference: (-0.00546736, -0.000142249)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.06 P-Value = 0.039<br><br />
<br />
Fisher's exact test: P-Value = 0.048<br><br />
<br />
“Efficacy” of 31.2% seems to be determined from<br><br />
(74 - 51)/ 74 = .310<br><br />
<br />
In the final column of the chart--“Strictly adheres to trial design”--appears the unreleased<br> “per protocol” version. According to<br> [http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html Science Magazine]: <br />
<br />
::The second analysis is called “per protocol” and adheres strictly to how the trial was designed by only including the study participants who got the full regimen of vaccine shots at the right time. Because it excludes study participants who didn't get the full vaccine regimen, it usually provides corroboration to the looser “intent to treat” findings.<br />
<br />
The article doesn’t say what the breakdown of the 86 infections is. Nevertheless, it indicates that the p-value of 16% puts a damper on enthusiasm for the vaccine.<br />
<br />
::The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong.”<br />
<br />
Discussion<br />
<br />
1. “Strictly adheres to trial design” has an efficacy of 26.2% and 86 infections. Show that this leads approximately to 36 and 50 infections, respectively. <br />
<br />
2. The articles fail to tell us the number of participants in the “per protocol” situation. However, use the 36 and 50 cited above and show via a statistics package such as Minitab that the Fisher exact test comes up with about 16% for the p-value regardless of whether the sample sizes are the original ones or 4000 each, 5000 each, etc.<br />
<br />
3. The “researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin… The debate over the way the results were presented will have no immediate practical impact because even under the most optimistic assessment, the vaccine offered too little protection to be a serious candidate for widespread use.” If this is so, why was there so much positive publicity in September?<br />
<br />
Submitted by Paul Alper<br />
<br />
<br />
<br />
-----<br />
<br />
==Carrying a gun increases risk of getting shot and killed==<br />
[http://www.newscientist.com/article/dn17922-carrying-a-gun-increases-risk-of-getting-shot-and-killed.html The NewScientist]<Br> <br />
October 06 2009 <br><br />
Ewen Callaway<br />
<br />
In this article we read<br />
<blockquote>People who carry guns are far likelier to get shot – and killed – than those who are unarmed, a study of shooting victims in Philadelphia, Pennsylvania, has found. It would be impractical – not to say unethical – to randomly assign volunteers to carry a gun or not and see what happens. So Charles Branas's team at the University of Pennsylvania analyzed 677 shootings over two-and-a-half years to discover whether victims were carrying at the time, and compared them to other Philly residents of similar age, sex and ethnicity. The team also accounted for other potentially confounding differences, such as the socioeconomic status of their neighborhood.</blockquote><br />
Their article will appear in the American Journal of Public Health. The current version of this article can be found [http://www.ajph.org/cgi/reprint/AJPH.2008.143099v1.pdf here] and the most resent abstract can be found [http://www.ajph.org/cgi/content/abstract/AJPH.2008.143099v1 here] in this abstract we read:<br><br><br />
<blockquote>Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.<br><br><br />
Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.<br><br><br />
Results. After adjustment, individuals in possession of a gun were 4.46 (P<.05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P<.05).<br><br><br />
Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.</blockquote><br />
<br />
Discussion<br />
<br />
Why do you think the New Science and other's discussing this study titled there article "Carrying a gun increases risk of getting shot and killed" rather than the title of of the article "Investigating the Link Between Gun Possession and Gun Assault"?<br />
<br />
Of course this is the kind of article that lends iself to interesting comments. For example:<br />
<br />
I am definitely going to have to find the complete article. I want to see how they determined which victims of being shot were included in the study and how they determined which civilians would be included in the study. With out that information, this study doesn't really mean anything.<br />
<br />
Follow this advice and see if you think the study really means anything.<br />
<br />
Sounds to me like a completely ignorant study and weighted to get the result they want. If you check a place like Philidelphia, of course this is the result you would get, because the people carrying guns are more likely to be involved in crimes or living in crime ridden areas. Check Dallas, or Oklahoma City. You wouldn't get that result at all. And that's because dang near everybody has guns, and we have far fewer shootings.<br />
<br />
Does this suggest that the study is completely ignorant?<br />
<br />
This article was suggested by Gordon Fox<br />
<br />
==Identifying financial market cycles - or not==<br />
[http://www.newyorker.com/reporting/2009/10/12/091012fa_fact_paumgarten “The Secret Cycle”], by Nick Paumgarten, <i>The New Yorker</i>, October 12, 2009<br><br />
<br />
This article focuses on the work of Martin Armstrong, a technical financial analyst, who found that, "on average, there had been a panic every 8.6 years" over the period 1683-1907:<br />
<blockquote>He discerned a recurrence of major turning points in the economy and in world affairs that followed a distinct and unwavering 8.6-year rhythm.</blockquote><br />
<br />
Then he found that the October 1987 crash “took place on the minor halfway point up the first leg of the 8.6-year cycle, at 2.15 years,” noting that "8.6 years was exactly … 3,141 [days], the number pi times a thousand.”<br><br />
<br />
Eventually:<br />
<blockquote>The model … failed, among other things, to foresee its developer’s demise. In September, 1999, Armstrong was charged with defrauding Japanese investors of nearly a billion dollars. …. The upshot, though, is that he has now spent more than nine years in jail – a pi cycle and then some.</blockquote><br />
<br />
The article includes discussions of Fibonacci-based market behavior models and the "reasoning" behind them.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Learning by the petabyte==<br />
<br />
[http://www.nytimes.com/2009/10/12/technology/12data.html Training to Climb an Everest of Digital Data]. Ashlee Vance, The New York Times, October 11, 2009.<br />
<br />
Some Statistics textbooks have been criticized for having small "toy" problems that do not reflect the complexity of data analysis out in the real world. What sort of data sets are out in the real world?<br />
<br />
<blockquote> Facebook, for example, uses more than 1 petabyte of storage space to manage its users’ 40 billion photos. It was not long ago that the notion of one company having anything close to 40 billion photos would have seemed tough to fathom. Google, meanwhile, churns through 20 times that amount of information every single day just running data analysis jobs. In short order, DNA sequencing systems too will generate many petabytes of information a year.</blockquote><br />
<br />
Even at the best universities, students are not asked to handle data sets this large. And this is a problem.<br />
<br />
<blockquote>For the most part, university students have used rather modest computing systems to support their studies. They are learning to collect and manipulate information on personal computers or what are known as clusters, where computer servers are cabled together to form a larger computer. But even these machines fail to churn through enough data to really challenge and train a young mind meant to ponder the mega-scale problems of tomorrow. "If they imprint on these small systems, that becomes their frame of reference and what they’re always thinking about," said Jim Spohrer, a director at I.B.M.'s Almaden Research Center. </blockquote><br />
<br />
Two companies with lots of experience tackling petabyte sized data sets want to change this.<br />
<br />
<blockquote>Two years ago, I.B.M. and Google set out to change the mindset at universities by giving students broad access to some of the largest computers on the planet. The companies then outfitted the computers with software that Internet companies use to tackle their toughest data analysis jobs. And, rather than building a big computer at each university, the companies created a system that let students and researchers tap into giant computers over the Internet. This year, the National Science Foundation, a federal government agency, issued a vote of confidence for the project by splitting $5 million among 14 universities that want to teach their students how to grapple with big data questions.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. What is the size of the largest data set that you have ever analyzed. Did the size of the data set force you to use a different computing system, different software, or a different statistical method?<br />
<br />
2. Could a random sample of a few megabytes from a petabyte of data be sufficiently useful to learn on? Note that a megabyte is six orders of magnitude smaller than a petabyte. Is it possible to have a representative sample with a data set sampled this sparsely?<br />
<br />
3. [http://en.wikipedia.org/wiki/Moore%27s_law Moore's Law] says (more or less) that computing capacity doubles every two years (some sources say 18 months). If Moore's Law applies, calculate how long will it take before we see petabyte sized hard drives on laptop computers?<br />
<br />
==The unluckiest fan==<br />
[http://www.npr.org/templates/story/story.php?storyId=113884165 Nats follower may be unluckiest fan]<br><br />
All Things Considered, NPR, 16 October 2009.<br />
<br />
The Washington Nationals baseball team posted a dismal won-lost record of 59-103 for the 2009 season. From the link above, you can listen to an interview with season-ticket holder Stephen Krupin, who watched the team lose all 19 games he attended this year. The host speculates that this must be a record for bad luck. In fact, Mr. Krupin reports that his cousin, a PhD economist, calculated the chance that this would happen as 1 in 131,204. <br />
<br />
In comments posted on the NPR site, several listeners attempt to reproduce this calculation, but find that the event appears to be more likely than reported. It turns out that their analyses are based on the full season record--which seems natural since that record is featured so prominently in the story. However, it comes out in the interview that Mr. Krupin attended only home games. From the [http://mlb.mlb.com/mlb/standings/ Major League Baseball standings] we see that the Nationals were 33–48 at home and 26–55 on the road. The chance that 19 randomly selected home games are all losses is <math>{48 \choose 19}/ {81 \choose 19} </math>, which equals 1 in 131203.8, in agreement with Mr. Krupin's report.<br />
<br />
We had another curious experience trying to get the data to match the calculation. An initial try found a [http://washington.nationals.mlb.com/schedule/sortable.jsp?c_id=was&year=2009 sortable schedule] on the Washington Nationals web site. Selecting the home games produces 85 entries: 34 wins, 48 losses and 3 postponements. Baseball fans will recognize that 34 plus 48 gives one too many home games, but how do we account for the extra win? It turns out that the May 5 game against the Astros was [http://www.usatoday.com/sports/baseball/2009-05-05-nats-astros-gamer_N.htm suspended by rain in the 11th inning], with the score tied 10-10. The game was completed on July 9, with the Nationals ultimately winning 11-10. This result appears twice in the schedule, once on each date. <br />
<br />
Submitted by Bill Peterson, based on a suggestion from Jeanne Albert.<br />
<br />
==More on who's happier==<br />
[http://languagelog.ldc.upenn.edu/nll/?p=1753 “The Happiness Gap is back is back is back is back”]<br><br />
by Mark Liberman, Language Log (online blog), September 20, 2009<br><br />
<br />
This is an update of Liberman's 2007 Language Log blog [http://itre.cis.upenn.edu/~myl/languagelog/archives/004965.html “The ‘Happiness Gap’ and the Rhetoric of Statistics”], which was posted in reaction to David Leonhardt’s 2007 <i>New York Times</i> article [http://www.nytimes.com/2007/09/26/business/26leonhardt.html?ex=1348545600&en=594e67d014f6dc88&ei=5124&partner=permalink&exprod=permalink “He’s Happier, She’s Less So”].<br><br />
<br />
He writes now in reaction to recently updated data and to the renewed spate of 2009 articles on this topic:<br> <br />
(a) NYT’s Ross Douthat in [http://www.nytimes.com/2009/05/26/opinion/26douthat.html?_r=1 “Liberated and Unhappy”]<br> <br />
(b) Huffington Post’s [http://www.huffingtonpost.com/arianna-huffington/the-sad-shocking-truth-ab_b_290021.html “The Sad, Shocking Truth About How Women Are Feeling”], [http://www.huffingtonpost.com/marcus-buckingham/whats-happening-to-womens_b_289511.html “What’s Happening To Women’s Happiness?”], <i>etc.</i><br> <br />
(c) NYT’s Marueen Dowd in [http://www.nytimes.com/2009/09/20/opinion/20dowd.html “Blue Is the New Black”].<br><br />
<br />
Here are the original and updated percents:<br><br />
<br />
1972-74<br> <br />
Men 31.9 very happy, 53.0 pretty happy, 15.1 not too happy<br><br />
Women 37.0 very happy, 49.4 pretty happy, 13.6 not too happy<br><br />
<br />
2004-08<br> <br />
Men 29.8 very happy, 56.1 pretty happy, 14.0 not too happy<br><br />
Women 31.2 very happy, 54.9 pretty happy, 13.9 not too happy<br><br />
<br />
Liberman refers readers to his more detailed 2007 discussion of the statistical issues – sample size, self-reporting, statistical vs. practical significance – including references to lots of other articles related to these survey results, in [http://itre.cis.upenn.edu/~myl/languagelog/archives/004987.html “The ‘Gender Happiness Gap’: Statistical, practical and rhetorical Significance”].<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Disc Fragments==<br />
<br />
The dream of every clinical trial is to come up with something which is inexpensive, definitive and likely to result in media publicity. “Improved outcome after lumbar microdiscectomy in patients shown their excised disc fragments: a prospective, double blind, randomized, controlled trial” by M.J. Tait, et al [http://www.ncbi.nlm.nih.gov/pubmed/19684238 here] fulfills the desire. <br />
<br />
According to local Twin Cities website with the heading, [http://www.minnpost.com/healthblog/2009/09/03/11307/seeing_it_appears_is_believing_when_it_comes_to_back_surgery Seeing, it appears, is believing when it comes to back surgery]: “British surgeons report that patients who underwent a surgical procedure (lumbar microdiscectomy) for back pain caused by a spinal disc tear (“slipped disc”) had better outcomes when they received fragments of their removed disc after the operation. That’s right. Simply taking home a souvenir of the operation in a pot of saline solution improved the patients’ recovery. They reported less leg and back pain, less leg weakness and less “pins and needles” sensations (paresthesia). They also took fewer pain medications after the surgery.”<br />
<br />
The surgeons “said they decided to do the study for two main reasons: They knew that a patient’s anxiety and depression going into surgery for a spinal disc tear has a big impact on the recovery process. They had also noticed, anecdotally, that many of their patients who responded best to the surgery — and who seemed to experience the least anxiety and depression afterwards — were those who had been given their disc fragments.”<br />
<br />
The abstract of the journal article notes low p-values to make their case “that presenting the removed disc material to patients after LMD improves patient outcome.”:<br />
<br />
<blockquote>Lumbar microdiscectomy (LMD) is a commonly performed neurosurgical procedure. We set up a prospective, double blind, randomised, controlled trial to test the hypothesis that presenting the removed disc material to patients after LMD improves patient outcome. METHODS: Adult patients undergoing LMD for radiculopathy caused by a prolapsed intervertebral disc were randomised into one of two groups, termed experimental and control. Patients in the experimental group were given their removed disc fragments whereas patients in the control group were not. Patients were unaware of the trial hypothesis and investigators were blinded to patient group allocation. Outcome was assessed between 3 and 6 months after LMD. Primary outcome measures were the degree of improvement in sciatica and back pain reported by the patients. Secondary outcome measures were the degree of improvement in leg weakness, paraesthesia, numbness, walking distance and use of analgesia reported by the patients. RESULTS: Data from 38 patients in the experimental group and 36 patients in the control groSummaryup were analysed. The two groups were matched for age, sex and preoperative symptoms. More patients in the experimental compared with the control group reported improvements in leg pain (91.5 vs 80.4%; p<0.05), back pain (86.1 vs 75.0%; p<0.05), limb weakness (90.5 vs 56.3%; p<0.02), paraesthesia (88 vs 61.9%; p<0.05) and reduced analgesic use (92.1 vs 69.4%; p<0.02) than preoperatively. CONCLUSION: Presentation of excised disc fragments is a cheap and effective way to improve outcome after LMD.</blockquote><br />
<br />
The entire paper is only three pages in length and so its calculations can be checked. Below are the calculation results for the three secondary outcomes for which the paper claims statistical significance:<br />
<br />
1. Improved Leg Weakness--the paper states that the p-value is less that .02. Minitab shows that the p-Fisher’s exact test is .024<br />
<br />
'''T and CI for Two Proportions''' [leg weakness]<br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">9</div></td><br />
<td><div align="center">16</div></td><br />
<td><div align="center">0.562500</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">19</div></td><br />
<td><div align="center">21</div></td><br />
<td><div align="center">0.904762</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.342262<br><br />
95% CI for difference: (-0.615844, -0.0686795)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.45 P-Value = 0.014<br />
<br />
Fisher's exact test: P-Value = 0.024<br />
<br />
2. Parathaesia--The paper states that the p-value is less that .05. Minitab shows that the p-value is from Fisher’s exact test is .08.<br />
<br />
Test and CI for Two Proportions [parathaesia]<br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">22</div></td><br />
<td><div align="center">25</div></td><br />
<td><div align="center">0.880000</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">13</div></td><br />
<td><div align="center">21</div></td><br />
<td><div align="center">0.619048</div></td><br />
</tr><br />
</table><br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.260952<br><br />
95% CI for difference: (0.0173021, 0.504603)<br><br />
Test for difference = 0 (vs not = 0): Z = 2.10 P-Value = 0.036<br />
<br />
Fisher's exact test: P-Value = 0.080<br />
<br />
3. Reduced Analgesic Use--The paper states that the p-value is less that .02. Minitab shows that the p-value from Fisher’s exact test is .017.<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">35</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">o.921053</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">25</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.694444</div></td><br />
</tr><br />
</table><br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.226608<br><br />
95% CI for difference: (0.0534229, 0.399793)<br><br />
Test for difference = 0 (vs not = 0): Z = 2.49 P-Value = 0.013<br />
<br />
Fisher's exact test: P-Value = 0.017<br />
<br />
The primary outcomes, leg pain and (low) back pain for the treatment vs. the control were not calculated in a similar manner to the way the secondary outcomes were. Instead of using a two-sample test of proportions, the results for “pain” were calculated by having five categories: “Much better,” Little better,” “Same,” “Little worse,” and “Much worse.” That is, an ordinal scale was employed. Because the accompanying graphs, Figure 1A and 1B in the paper, are not precise enough to determine the number in each category, a nonparametric calculation is hard to carry out.<br />
<br />
Nevertheless, ignoring the breakdown into five categories, here are Minitab results for leg pain and back pain, respectively; note that the p-values are much different from the claimed <.05:<br />
<br />
Test and CI for Two Proportions [leg pain]<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">35</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.921053</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">29</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.805556</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.115497<br><br />
95% CI for difference: (-0.0396318, 0.270626)<br><br />
Test for difference = 0 (vs not = 0): Z = 1.46 P-Value = 0.144<br />
<br />
Fisher's exact test: P-Value = 0.185<br />
<br />
Test and CI for Two Proportions [back pain]<br />
Sample X N Sample p <br />
1 33 38 0.868421<br />
2 27 36 0.750000<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">33</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.868421</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">27</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.750000</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.118421<br><br />
95% CI for difference: (-0.0592271, 0.296069)<br><br />
Test for difference = 0 (vs not = 0): Z = 1.31 P-Value = 0.191<br />
<br />
Fisher's exact test: P-Value = 0.242 <br />
<br />
Discussion<br />
<br />
1. Why might an individual report a better outcome because he was handed his disc fragment? Why might he feel worse?<br />
<br />
2. Assuming that the p-values reported in the article are correct, what criticism might still remain?<br />
<br />
3. A disc fragment is one form of excised body part. What other excised body part might have a similar positive result? What other excise body part might have a distinctly negative result?<br />
<br />
4. This study took place in London, England. Why might patient reaction be different in, let us say, Asia or Africa?<br />
<br />
Submitted by Paul Alper<br />
<br />
<br />
<br />
<br />
'''Test and CI for Two Proportions''' [leg pain]<br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">35</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.921053</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">29</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.805556</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.115497<br />
95% CI for difference: (-0.0396318, 0.270626)<br />
Test for difference = 0 (vs not = 0): Z = 1.46 P-Value = 0.144<br />
<br />
Fisher's exact test: P-Value = 0.185<br />
<br />
'''Test and CI for Two Proportions''' [back pain]<br />
Sample X N Sample p <br />
1 33 38 0.868421<br />
2 27 36 0.750000<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">33</div></td><br />
<td><div align="center">38</div></td><br />
<td><div align="center">0.868421</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">27</div></td><br />
<td><div align="center">36</div></td><br />
<td><div align="center">0.750000</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.118421<br />
95% CI for difference: (-0.0592271, 0.296069)<br />
Test for difference = 0 (vs not = 0): Z = 1.31 P-Value = 0.191<br />
<br />
Fisher's exact test: P-Value = 0.242 <br />
<br />
Discussion<br />
<br />
1. Why might an individual report a better outcome because he was handed his disc fragment? Why might he feel worse?<br />
<br />
2. Assuming that the p-values reported in the article are correct, what criticism might still remain?<br />
<br />
3. A disc fragment is one form of excised body part. What other excised body part might have a similar positive result? What other excise body part might have a distinctly negative result?<br />
<br />
4. This study took place in London, England. Why might patient reaction be different in, let us say, Asia or Africa?<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_56&diff=9405Chance News 562009-10-16T02:21:13Z<p>PaulAlper: /* More on AIDS Vaccine */</p>
<hr />
<div>==Quotations==<br />
<br />
<center><blockquote> I can calculate the motion of heavenly<br> bodies but not the madness of people</blockquote></center><br />
<br />
<div align="right">Isaac Newton<br><br />
After losing a fortune in the<br> South Sea Company bubble of 1720</div><br />
<br />
----<br />
Trying is the first step towards failure. -- Homer Simpson<br />
<br />
== Forsooths==<br />
<br />
This forsooth is from the October 2009 RSS Forsooth. <br />
<br />
<blockquote>Of course in those days we worked on the assumption that everything was normally distributed and we have seen in the last few months that there is no such thing as a normal distribution. <br />
<div align="right">Scientific Computing World<br><br />
February/March 2009</div></blockquote><br />
<br />
You can see the context of this comment [http://www.scientific-computing.com/features/feature.php?feature_id=223 here].<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
<br />
According to a <i>New Yorker</i> (October 12, 2009) review [http://www.newyorker.com/arts/critics/atlarge/2009/10/12/091012crat_atlarge_lepore] of Matthew Stewart's <i>The Management Myth: Why the Experts Keep Getting It Wrong</i>, Stewart tells a story about how "his boss taught his twenty-something[-old] trainees ... how to conduct a 'two-handed regression'":<blockquote>"When a scatter plot failed to show the signifiant correlation between two variables that we all knew was there, he would place a pair of meaty hands over the offending clouds of data points and thereby reveal the straight line hiding from conventional mathematics." Management consulting isn't a science, Stewart says; it's a party trick.</blockquote><br />
<br />
==Minimizing the number of coins jingling in your pocket==<br />
<br />
[http://freakonomics.blogs.nytimes.com/2009/10/06/do-we-need-a-37-cent-coin/ Do We Need a 37-Cent Coin?] Steven d. Levitt, October 6, 2009, Freakonomics Blog, The New York Times.<br />
<br />
The current system of coins in the United States is inefficient. Patrick DeJarnette studied this problem and his work was highlighted in the Freakonomics blog. Dr. DeJarnette makes two assumptions.<br />
<br />
<blockquote>1. Some combination of coins must reach every integer value in [0,99].</blockquote><br />
<br />
<blockquote>2. Probability of a transaction resulting in value v is uniform from [0,99].</blockquote><br />
<br />
Under this system, the average number of coins that you would receive in change during a random transaction would be 4.7. The system that would work better is rather bizzarre.<br />
<br />
<blockquote>The most efficient systems? The penny, 3-cent piece, 11-cent piece, 37-cent piece, and (1,3,11,38) are tied at 4.10 coins per transaction.</blockquote><br />
<br />
Such a set of coins would be evocative of the [http://en.wikipedia.org/wiki/Harry_Potter_universe#Coins monetary system in the Harry Potter books].<br />
<br />
The article goes on to discuss systems where the coins are more conveniently priced and which single change in coins would lead to the greatest savings.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Minimizing the number of coins received in change is not the only criteria for a set of coin denominations. What other criteria make sense.<br />
<br />
2. Is it logical to assume a uniform distribution in this problem?<br />
<br />
3. What coin could be added to the current mix of coins to minimize the number of coins given in change.<br />
<br />
==Failure to disclose==<br />
[http://online.wsj.com/article/SB125511780864976689.html#articleTabs%3Darticle “Data Call Into Question HIV Study Results”]<br><br />
by Gautam Naik and Mark Schoofs, <i>The Wall Street Journal</i>, October 10, 2009<br><br />
<br />
Researchers from the U.S. Army and Thailand failed to disclose that some results of a potential HIV vaccine trial were not statistically significant, although they had this information when they announced the discovery.<br />
<br />
<blockquote>"We thought very hard about how to provide the clearest, most honest message," [one researcher] said. "We stand by the fact that this is a vaccine with a modest protective effect." He called the trial results "complex."</blockquote><br />
<br />
The first analysis, a “modified intent to treat” analysis, included “virtually everyone who enrolled in the study, regardless of whether they ended up getting the full course of the vaccine. …. By this measure, the vaccine tested in Thailand reduced by 31% the chance of infection with HIV ….”<br />
<br />
<blockquote>New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots. Statistical calculations showed there was a 3.9% probability that chance accounted for the difference. In drug and vaccine trials, anything above a 5% probability of a chance result is deemed statistically insignificant.</blockquote><br />
<br />
The second analysis, a “per protocol” analysis, included only the “study participants who got the full regimen of vaccine shots at the right time.” Apparently, for this group, in which 86 people were infected, there is a “16% chance the study results were a fluke.” It reduced by 26% the chance of infection with HIV.<br><br />
<br />
The article’s authors comment:<br />
<blockquote>It isn't clear why the vaccine was seemingly ineffective among participants who followed the guidelines to the letter.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
==More on AIDS Vaccine==<br />
<br />
“Hardly ever believe what you read” is a maxim that will stand you in good stead. Googling “aids vaccine Thailand” will get 248,000 hits, most of which are misleading. In essence, the URLs say that for the first time an effective vaccine against AIDS has been manufactured. But that was last month. Reality has now set in.<br />
<br />
The following chart found in [http://online.wsj.com/article/SB125511780864976689.html the Wall Street Journal of October 9, 2009] paints a different picture. “New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots.” Note that the “125” infections represent “51 + 74.”<br />
<br />
<br />
<center> http://www.dartmouth.edu/~chance/forwiki/HiV.gif</center><br />
<br />
The announcement on September 24, 2009 indicated that the p-value is 3.9%. A Minitab run shows that, in fact, the p-value is higher (i.e., worse) as indicated by the Fisher exact test. However, the .048 is still under the mystical .05:<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">51</div></td><br />
<td><div align="center">8197</div></td><br />
<td><div align="center">0.006222</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">74</div></td><br />
<td><div align="center">8198</div></td><br />
<td><div align="center">0.009027</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.00280480<br><br />
95% CI for difference: (-0.00546736, -0.000142249)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.06 P-Value = 0.039<br><br />
<br />
Fisher's exact test: P-Value = 0.048<br><br />
<br />
“Efficacy” of 31.2% seems to be determined from<br><br />
(74 - 51)/ 74 = .310<br><br />
<br />
In the final column of the chart--“Strictly adheres to trial design”--appears the unreleased<br> “per protocol” version. According to<br> [http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html Science Magazine]: <br />
<br />
::The second analysis is called “per protocol” and adheres strictly to how the trial was designed by only including the study participants who got the full regimen of vaccine shots at the right time. Because it excludes study participants who didn't get the full vaccine regimen, it usually provides corroboration to the looser “intent to treat” findings.<br />
<br />
The article doesn’t say what the breakdown of the 86 infections is. Nevertheless, it indicates that the p-value of 16% puts a damper on enthusiasm for the vaccine.<br />
<br />
::The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong.”<br />
<br />
Discussion<br />
<br />
1. “Strictly adheres to trial design” has an efficacy of 26.2% and 86 infections. Show that this leads approximately to 36 and 50 infections, respectively. <br />
<br />
2. The articles fail to tell us the number of participants in the “per protocol” situation. However, use the 36 and 50 cited above and show via a statistics package such as Minitab that the Fisher exact test comes up with about 16% for the p-value regardless of whether the sample sizes are the original ones or 4000 each, 5000 each, etc.<br />
<br />
3. The “researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin… The debate over the way the results were presented will have no immediate practical impact because even under the most optimistic assessment, the vaccine offered too little protection to be a serious candidate for widespread use.” If this is so, why was there so much positive publicity in September?<br />
<br />
Submitted by Paul Alper<br />
<br />
<br />
<br />
-----<br />
<br />
==Carrying a gun increases risk of getting shot and killed==<br />
[http://www.newscientist.com/article/dn17922-carrying-a-gun-increases-risk-of-getting-shot-and-killed.html The NewScientist]<Br> <br />
October 06 2009 <br><br />
Ewen Callaway<br />
<br />
In this article we read<br />
<blockquote>People who carry guns are far likelier to get shot – and killed – than those who are unarmed, a study of shooting victims in Philadelphia, Pennsylvania, has found. It would be impractical – not to say unethical – to randomly assign volunteers to carry a gun or not and see what happens. So Charles Branas's team at the University of Pennsylvania analyzed 677 shootings over two-and-a-half years to discover whether victims were carrying at the time, and compared them to other Philly residents of similar age, sex and ethnicity. The team also accounted for other potentially confounding differences, such as the socioeconomic status of their neighborhood.</blockquote><br />
Their article will appear in the American Journal of Public Health. The current version of this article can be found [http://www.ajph.org/cgi/reprint/AJPH.2008.143099v1.pdf here] and the most resent abstract can be found [http://www.ajph.org/cgi/content/abstract/AJPH.2008.143099v1 here] in this abstract we read:<br><br><br />
<blockquote>Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.<br><br><br />
Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.<br><br><br />
Results. After adjustment, individuals in possession of a gun were 4.46 (P<.05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P<.05).<br><br><br />
Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.</blockquote><br />
<br />
Discussion<br />
<br />
Why do you think the New Science and other's discussing this study titled there article "Carrying a gun increases risk of getting shot and killed" rather than the title of of the article "Investigating the Link Between Gun Possession and Gun Assault"?<br />
<br />
Of course this is the kind of article that lends iself to interesting comments. For example:<br />
<br />
I am definitely going to have to find the complete article. I want to see how they determined which victims of being shot were included in the study and how they determined which civilians would be included in the study. With out that information, this study doesn't really mean anything.<br />
<br />
Follow this advice and see if you think the study really means anything.<br />
<br />
Sounds to me like a completely ignorant study and weighted to get the result they want. If you check a place like Philidelphia, of course this is the result you would get, because the people carrying guns are more likely to be involved in crimes or living in crime ridden areas. Check Dallas, or Oklahoma City. You wouldn't get that result at all. And that's because dang near everybody has guns, and we have far fewer shootings.<br />
<br />
Does this suggest that the study is completely ignorant?<br />
<br />
This article was suggested by Gordon Fox<br />
<br />
==Identifying financial market cycles - or not==<br />
[http://www.newyorker.com/reporting/2009/10/12/091012fa_fact_paumgarten “The Secret Cycle”], by Nick Paumgarten, <i>The New Yorker</i>, October 12, 2009<br><br />
<br />
This article focuses on the work of Martin Armstrong, a technical financial analyst, who found that, "on average, there had been a panic every 8.6 years" over the period 1683-1907:<br />
<blockquote>He discerned a recurrence of major turning points in the economy and in world affairs that followed a distinct and unwavering 8.6-year rhythm.</blockquote><br />
<br />
Then he found that the October 1987 crash “took place on the minor halfway point up the first leg of the 8.6-year cycle, at 2.15 years,” noting that "8.6 years was exactly … 3,141 [days], the number pi times a thousand.”<br><br />
<br />
Eventually:<br />
<blockquote>The model … failed, among other things, to foresee its developer’s demise. In September, 1999, Armstrong was charged with defrauding Japanese investors of nearly a billion dollars. …. The upshot, though, is that he has now spent more than nine years in jail – a pi cycle and then some.</blockquote><br />
<br />
The article includes discussions of Fibonacci-based market behavior models and the "reasoning" behind them.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Learning by the petabyte==<br />
<br />
[http://www.nytimes.com/2009/10/12/technology/12data.html Training to Climb an Everest of Digital Data]. Ashlee Vance, The New York Times, October 11, 2009.<br />
<br />
Some Statistics textbooks have been criticized for having small "toy" problems that do not reflect the complexity of data analysis out in the real world. What sort of data sets are out in the real world?<br />
<br />
<blockquote> Facebook, for example, uses more than 1 petabyte of storage space to manage its users’ 40 billion photos. It was not long ago that the notion of one company having anything close to 40 billion photos would have seemed tough to fathom. Google, meanwhile, churns through 20 times that amount of information every single day just running data analysis jobs. In short order, DNA sequencing systems too will generate many petabytes of information a year.</blockquote><br />
<br />
Even at the best universities, students are not asked to handle data sets this large. And this is a problem.<br />
<br />
<blockquote>For the most part, university students have used rather modest computing systems to support their studies. They are learning to collect and manipulate information on personal computers or what are known as clusters, where computer servers are cabled together to form a larger computer. But even these machines fail to churn through enough data to really challenge and train a young mind meant to ponder the mega-scale problems of tomorrow. "If they imprint on these small systems, that becomes their frame of reference and what they’re always thinking about," said Jim Spohrer, a director at I.B.M.'s Almaden Research Center. </blockquote><br />
<br />
Two companies with lots of experience tackling petabyte sized data sets want to change this.<br />
<br />
<blockquote>Two years ago, I.B.M. and Google set out to change the mindset at universities by giving students broad access to some of the largest computers on the planet. The companies then outfitted the computers with software that Internet companies use to tackle their toughest data analysis jobs. And, rather than building a big computer at each university, the companies created a system that let students and researchers tap into giant computers over the Internet. This year, the National Science Foundation, a federal government agency, issued a vote of confidence for the project by splitting $5 million among 14 universities that want to teach their students how to grapple with big data questions.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. What is the size of the largest data set that you have ever analyzed. Did the size of the data set force you to use a different computing system, different software, or a different statistical method?<br />
<br />
2. Could a random sample of a few megabytes from a petabyte of data be sufficiently useful to learn on? Note that a megabyte is six orders of magnitude smaller than a petabyte. Is it possible to have a representative sample with a data set sampled this sparsely?<br />
<br />
3. [http://en.wikipedia.org/wiki/Moore%27s_law Moore's Law] says (more or less) that computing capacity doubles every two years (some sources say 18 months). If Moore's Law applies, calculate how long will it take before we see petabyte sized hard drives on laptop computers?.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_56&diff=9391Chance News 562009-10-16T02:20:29Z<p>PaulAlper: /* Forsooths */</p>
<hr />
<div>==Quotations==<br />
<br />
<center><blockquote> I can calculate the motion of heavenly<br> bodies but not the madness of people</blockquote></center><br />
<br />
<div align="right">Isaac Newton<br><br />
After losing a fortune in the<br> South Sea Company bubble of 1720</div><br />
<br />
----<br />
Trying is the first step towards failure. -- Homer Simpson<br />
<br />
== Forsooths==<br />
<br />
This forsooth is from the October 2009 RSS Forsooth. <br />
<br />
<blockquote>Of course in those days we worked on the assumption that everything was normally distributed and we have seen in the last few months that there is no such thing as a normal distribution. <br />
<div align="right">Scientific Computing World<br><br />
February/March 2009</div></blockquote><br />
<br />
You can see the context of this comment [http://www.scientific-computing.com/features/feature.php?feature_id=223 here].<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
<br />
According to a <i>New Yorker</i> (October 12, 2009) review [http://www.newyorker.com/arts/critics/atlarge/2009/10/12/091012crat_atlarge_lepore] of Matthew Stewart's <i>The Management Myth: Why the Experts Keep Getting It Wrong</i>, Stewart tells a story about how "his boss taught his twenty-something[-old] trainees ... how to conduct a 'two-handed regression'":<blockquote>"When a scatter plot failed to show the signifiant correlation between two variables that we all knew was there, he would place a pair of meaty hands over the offending clouds of data points and thereby reveal the straight line hiding from conventional mathematics." Management consulting isn't a science, Stewart says; it's a party trick.</blockquote><br />
<br />
==Minimizing the number of coins jingling in your pocket==<br />
<br />
[http://freakonomics.blogs.nytimes.com/2009/10/06/do-we-need-a-37-cent-coin/ Do We Need a 37-Cent Coin?] Steven d. Levitt, October 6, 2009, Freakonomics Blog, The New York Times.<br />
<br />
The current system of coins in the United States is inefficient. Patrick DeJarnette studied this problem and his work was highlighted in the Freakonomics blog. Dr. DeJarnette makes two assumptions.<br />
<br />
<blockquote>1. Some combination of coins must reach every integer value in [0,99].</blockquote><br />
<br />
<blockquote>2. Probability of a transaction resulting in value v is uniform from [0,99].</blockquote><br />
<br />
Under this system, the average number of coins that you would receive in change during a random transaction would be 4.7. The system that would work better is rather bizzarre.<br />
<br />
<blockquote>The most efficient systems? The penny, 3-cent piece, 11-cent piece, 37-cent piece, and (1,3,11,38) are tied at 4.10 coins per transaction.</blockquote><br />
<br />
Such a set of coins would be evocative of the [http://en.wikipedia.org/wiki/Harry_Potter_universe#Coins monetary system in the Harry Potter books].<br />
<br />
The article goes on to discuss systems where the coins are more conveniently priced and which single change in coins would lead to the greatest savings.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Minimizing the number of coins received in change is not the only criteria for a set of coin denominations. What other criteria make sense.<br />
<br />
2. Is it logical to assume a uniform distribution in this problem?<br />
<br />
3. What coin could be added to the current mix of coins to minimize the number of coins given in change.<br />
<br />
==Failure to disclose==<br />
[http://online.wsj.com/article/SB125511780864976689.html#articleTabs%3Darticle “Data Call Into Question HIV Study Results”]<br><br />
by Gautam Naik and Mark Schoofs, <i>The Wall Street Journal</i>, October 10, 2009<br><br />
<br />
Researchers from the U.S. Army and Thailand failed to disclose that some results of a potential HIV vaccine trial were not statistically significant, although they had this information when they announced the discovery.<br />
<br />
<blockquote>"We thought very hard about how to provide the clearest, most honest message," [one researcher] said. "We stand by the fact that this is a vaccine with a modest protective effect." He called the trial results "complex."</blockquote><br />
<br />
The first analysis, a “modified intent to treat” analysis, included “virtually everyone who enrolled in the study, regardless of whether they ended up getting the full course of the vaccine. …. By this measure, the vaccine tested in Thailand reduced by 31% the chance of infection with HIV ….”<br />
<br />
<blockquote>New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots. Statistical calculations showed there was a 3.9% probability that chance accounted for the difference. In drug and vaccine trials, anything above a 5% probability of a chance result is deemed statistically insignificant.</blockquote><br />
<br />
The second analysis, a “per protocol” analysis, included only the “study participants who got the full regimen of vaccine shots at the right time.” Apparently, for this group, in which 86 people were infected, there is a “16% chance the study results were a fluke.” It reduced by 26% the chance of infection with HIV.<br><br />
<br />
The article’s authors comment:<br />
<blockquote>It isn't clear why the vaccine was seemingly ineffective among participants who followed the guidelines to the letter.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
==More on AIDS Vaccine==<br />
<br />
“Hardly ever believe what you read” is a maxim that will stand you in good stead. Googling “aids vaccine Thailand” will get 248,000 hits, most of which are misleading. In essence, the URLs say that for the first time an effective vaccine against AIDS has been manufactured. But that was last month. Reality has now set in.<br />
<br />
The following chart found in [http://online.wsj.com/article/SB125511780864976689.html the Wall Street Journal of October 9, 2009] paints a different picture. “New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots.” Note that the “125” infections represent “51 + 74.”<br />
<br />
<br />
<center> http://www.dartmouth.edu/~chance/forwiki/HiV.gif</center><br />
<br />
The announcement on September 24, 2009 indicated that the p-value is 3.9%. A Minitab run shows that, in fact, the p-value is higher (i.e., worse) as indicated by the Fisher exact test. However, the .048 is still under the mystical .05:<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">51</div></td><br />
<td><div align="center">8197</div></td><br />
<td><div align="center">0.006222</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">74</div></td><br />
<td><div align="center">8198</div></td><br />
<td><div align="center">0.009027</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.00280480<br><br />
95% CI for difference: (-0.00546736, -0.000142249)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.06 P-Value = 0.039<br><br />
<br />
Fisher's exact test: P-Value = 0.048<br><br />
<br />
“Efficacy” of 31.2% seems to be determined from<br><br />
(74 - 51)/ 74 = .310<br><br />
<br />
In the final column of the chart--“Strictly adheres to trial design”--appears the unreleased<br> “per protocol” version. According to<br> [http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html Science Magazine]: <br />
<br />
::The second analysis is called “per protocol” and adheres strictly to how the trial was designed by only including the study participants who got the full regimen of vaccine shots at the right time. Because it excludes study participants who didn't get the full vaccine regimen, it usually provides corroboration to the looser “intent to treat” findings.<br />
<br />
The article doesn’t say what the breakdown of the 86 infections is. Nevertheless, it indicates that the p-value of 16% puts a damper on enthusiasm for the vaccine.<br />
<br />
::The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong.”<br />
<br />
Discussion<br />
<br />
1. “Strictly adheres to trial design” has an efficacy of 26.2% and 86 infections. Show that this leads approximately to 36 and 50 infections, respectively. <br />
<br />
2. The articles fail to tell us the number of participants in the “per protocol” situation. However, use the 36 and 50 cited above and show via a statistics package such as Minitab that the Fisher exact test comes up with about 16% for the p-value regardless of whether the sample sizes are the original ones or 4000 each, 5000 each, etc.<br />
<br />
3. The “researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin… The debate over the way the results were presented will have no immediate practical impact because even under the most optimistic assessment, the vaccine offered too little protection to be a serious candidate for widespread use.” If this is so, why was there so much positive publicity in September?<br />
<br />
Submitted by Paul Alper<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
-----<br />
<br />
==Carrying a gun increases risk of getting shot and killed==<br />
[http://www.newscientist.com/article/dn17922-carrying-a-gun-increases-risk-of-getting-shot-and-killed.html The NewScientist]<Br> <br />
October 06 2009 <br><br />
Ewen Callaway<br />
<br />
In this article we read<br />
<blockquote>People who carry guns are far likelier to get shot – and killed – than those who are unarmed, a study of shooting victims in Philadelphia, Pennsylvania, has found. It would be impractical – not to say unethical – to randomly assign volunteers to carry a gun or not and see what happens. So Charles Branas's team at the University of Pennsylvania analyzed 677 shootings over two-and-a-half years to discover whether victims were carrying at the time, and compared them to other Philly residents of similar age, sex and ethnicity. The team also accounted for other potentially confounding differences, such as the socioeconomic status of their neighborhood.</blockquote><br />
Their article will appear in the American Journal of Public Health. The current version of this article can be found [http://www.ajph.org/cgi/reprint/AJPH.2008.143099v1.pdf here] and the most resent abstract can be found [http://www.ajph.org/cgi/content/abstract/AJPH.2008.143099v1 here] in this abstract we read:<br><br><br />
<blockquote>Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.<br><br><br />
Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.<br><br><br />
Results. After adjustment, individuals in possession of a gun were 4.46 (P<.05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P<.05).<br><br><br />
Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.</blockquote><br />
<br />
Discussion<br />
<br />
Why do you think the New Science and other's discussing this study titled there article "Carrying a gun increases risk of getting shot and killed" rather than the title of of the article "Investigating the Link Between Gun Possession and Gun Assault"?<br />
<br />
Of course this is the kind of article that lends iself to interesting comments. For example:<br />
<br />
I am definitely going to have to find the complete article. I want to see how they determined which victims of being shot were included in the study and how they determined which civilians would be included in the study. With out that information, this study doesn't really mean anything.<br />
<br />
Follow this advice and see if you think the study really means anything.<br />
<br />
Sounds to me like a completely ignorant study and weighted to get the result they want. If you check a place like Philidelphia, of course this is the result you would get, because the people carrying guns are more likely to be involved in crimes or living in crime ridden areas. Check Dallas, or Oklahoma City. You wouldn't get that result at all. And that's because dang near everybody has guns, and we have far fewer shootings.<br />
<br />
Does this suggest that the study is completely ignorant?<br />
<br />
This article was suggested by Gordon Fox<br />
<br />
==Identifying financial market cycles - or not==<br />
[http://www.newyorker.com/reporting/2009/10/12/091012fa_fact_paumgarten “The Secret Cycle”], by Nick Paumgarten, <i>The New Yorker</i>, October 12, 2009<br><br />
<br />
This article focuses on the work of Martin Armstrong, a technical financial analyst, who found that, "on average, there had been a panic every 8.6 years" over the period 1683-1907:<br />
<blockquote>He discerned a recurrence of major turning points in the economy and in world affairs that followed a distinct and unwavering 8.6-year rhythm.</blockquote><br />
<br />
Then he found that the October 1987 crash “took place on the minor halfway point up the first leg of the 8.6-year cycle, at 2.15 years,” noting that "8.6 years was exactly … 3,141 [days], the number pi times a thousand.”<br><br />
<br />
Eventually:<br />
<blockquote>The model … failed, among other things, to foresee its developer’s demise. In September, 1999, Armstrong was charged with defrauding Japanese investors of nearly a billion dollars. …. The upshot, though, is that he has now spent more than nine years in jail – a pi cycle and then some.</blockquote><br />
<br />
The article includes discussions of Fibonacci-based market behavior models and the "reasoning" behind them.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Learning by the petabyte==<br />
<br />
[http://www.nytimes.com/2009/10/12/technology/12data.html Training to Climb an Everest of Digital Data]. Ashlee Vance, The New York Times, October 11, 2009.<br />
<br />
Some Statistics textbooks have been criticized for having small "toy" problems that do not reflect the complexity of data analysis out in the real world. What sort of data sets are out in the real world?<br />
<br />
<blockquote> Facebook, for example, uses more than 1 petabyte of storage space to manage its users’ 40 billion photos. It was not long ago that the notion of one company having anything close to 40 billion photos would have seemed tough to fathom. Google, meanwhile, churns through 20 times that amount of information every single day just running data analysis jobs. In short order, DNA sequencing systems too will generate many petabytes of information a year.</blockquote><br />
<br />
Even at the best universities, students are not asked to handle data sets this large. And this is a problem.<br />
<br />
<blockquote>For the most part, university students have used rather modest computing systems to support their studies. They are learning to collect and manipulate information on personal computers or what are known as clusters, where computer servers are cabled together to form a larger computer. But even these machines fail to churn through enough data to really challenge and train a young mind meant to ponder the mega-scale problems of tomorrow. "If they imprint on these small systems, that becomes their frame of reference and what they’re always thinking about," said Jim Spohrer, a director at I.B.M.'s Almaden Research Center. </blockquote><br />
<br />
Two companies with lots of experience tackling petabyte sized data sets want to change this.<br />
<br />
<blockquote>Two years ago, I.B.M. and Google set out to change the mindset at universities by giving students broad access to some of the largest computers on the planet. The companies then outfitted the computers with software that Internet companies use to tackle their toughest data analysis jobs. And, rather than building a big computer at each university, the companies created a system that let students and researchers tap into giant computers over the Internet. This year, the National Science Foundation, a federal government agency, issued a vote of confidence for the project by splitting $5 million among 14 universities that want to teach their students how to grapple with big data questions.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. What is the size of the largest data set that you have ever analyzed. Did the size of the data set force you to use a different computing system, different software, or a different statistical method?<br />
<br />
2. Could a random sample of a few megabytes from a petabyte of data be sufficiently useful to learn on? Note that a megabyte is six orders of magnitude smaller than a petabyte. Is it possible to have a representative sample with a data set sampled this sparsely?<br />
<br />
3. [http://en.wikipedia.org/wiki/Moore%27s_law Moore's Law] says (more or less) that computing capacity doubles every two years (some sources say 18 months). If Moore's Law applies, calculate how long will it take before we see petabyte sized hard drives on laptop computers?.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_56&diff=9390Chance News 562009-10-16T02:14:42Z<p>PaulAlper: /* More on AIDS Vaccine */</p>
<hr />
<div>==Quotations==<br />
<br />
<center><blockquote> I can calculate the motion of heavenly<br> bodies but not the madness of people</blockquote></center><br />
<br />
<div align="right">Isaac Newton<br><br />
After losing a fortune in the<br> South Sea Company bubble of 1720</div><br />
<br />
----<br />
Trying is the first step towards failure. -- Homer Simpson<br />
<br />
== Forsooths==<br />
<br />
This forsooth is from the October 2009 RSS Forsooth. <br />
<br />
<blockquote>Of course in those days we worked on the assumption that everything was normally distributed and we have seen in the last few months that there is no such thing as a normal distribution. <br />
<div align="right">Scientific Computing World<br><br />
February/March 2009</div></blockquote><br />
<br />
You can see the context of this comment [http://www.scientific-computing.com/features/feature.php?feature_id=223 here].<br />
<br />
<br />
According to a <i>New Yorker</i> (October 12, 2009) review [http://www.newyorker.com/arts/critics/atlarge/2009/10/12/091012crat_atlarge_lepore] of Matthew Stewart's <i>The Management Myth: Why the Experts Keep Getting It Wrong</i>, Stewart tells a story about how "his boss taught his twenty-something[-old] trainees ... how to conduct a 'two-handed regression'":<blockquote>"When a scatter plot failed to show the signifiant correlation between two variables that we all knew was there, he would place a pair of meaty hands over the offending clouds of data points and thereby reveal the straight line hiding from conventional mathematics." Management consulting isn't a science, Stewart says; it's a party trick.</blockquote><br />
<br />
==Minimizing the number of coins jingling in your pocket==<br />
<br />
[http://freakonomics.blogs.nytimes.com/2009/10/06/do-we-need-a-37-cent-coin/ Do We Need a 37-Cent Coin?] Steven d. Levitt, October 6, 2009, Freakonomics Blog, The New York Times.<br />
<br />
The current system of coins in the United States is inefficient. Patrick DeJarnette studied this problem and his work was highlighted in the Freakonomics blog. Dr. DeJarnette makes two assumptions.<br />
<br />
<blockquote>1. Some combination of coins must reach every integer value in [0,99].</blockquote><br />
<br />
<blockquote>2. Probability of a transaction resulting in value v is uniform from [0,99].</blockquote><br />
<br />
Under this system, the average number of coins that you would receive in change during a random transaction would be 4.7. The system that would work better is rather bizzarre.<br />
<br />
<blockquote>The most efficient systems? The penny, 3-cent piece, 11-cent piece, 37-cent piece, and (1,3,11,38) are tied at 4.10 coins per transaction.</blockquote><br />
<br />
Such a set of coins would be evocative of the [http://en.wikipedia.org/wiki/Harry_Potter_universe#Coins monetary system in the Harry Potter books].<br />
<br />
The article goes on to discuss systems where the coins are more conveniently priced and which single change in coins would lead to the greatest savings.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Minimizing the number of coins received in change is not the only criteria for a set of coin denominations. What other criteria make sense.<br />
<br />
2. Is it logical to assume a uniform distribution in this problem?<br />
<br />
3. What coin could be added to the current mix of coins to minimize the number of coins given in change.<br />
<br />
==Failure to disclose==<br />
[http://online.wsj.com/article/SB125511780864976689.html#articleTabs%3Darticle “Data Call Into Question HIV Study Results”]<br><br />
by Gautam Naik and Mark Schoofs, <i>The Wall Street Journal</i>, October 10, 2009<br><br />
<br />
Researchers from the U.S. Army and Thailand failed to disclose that some results of a potential HIV vaccine trial were not statistically significant, although they had this information when they announced the discovery.<br />
<br />
<blockquote>"We thought very hard about how to provide the clearest, most honest message," [one researcher] said. "We stand by the fact that this is a vaccine with a modest protective effect." He called the trial results "complex."</blockquote><br />
<br />
The first analysis, a “modified intent to treat” analysis, included “virtually everyone who enrolled in the study, regardless of whether they ended up getting the full course of the vaccine. …. By this measure, the vaccine tested in Thailand reduced by 31% the chance of infection with HIV ….”<br />
<br />
<blockquote>New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots. Statistical calculations showed there was a 3.9% probability that chance accounted for the difference. In drug and vaccine trials, anything above a 5% probability of a chance result is deemed statistically insignificant.</blockquote><br />
<br />
The second analysis, a “per protocol” analysis, included only the “study participants who got the full regimen of vaccine shots at the right time.” Apparently, for this group, in which 86 people were infected, there is a “16% chance the study results were a fluke.” It reduced by 26% the chance of infection with HIV.<br><br />
<br />
The article’s authors comment:<br />
<blockquote>It isn't clear why the vaccine was seemingly ineffective among participants who followed the guidelines to the letter.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
==More on AIDS Vaccine==<br />
<br />
“Hardly ever believe what you read” is a maxim that will stand you in good stead. Googling “aids vaccine Thailand” will get 248,000 hits, most of which are misleading. In essence, the URLs say that for the first time an effective vaccine against AIDS has been manufactured. But that was last month. Reality has now set in.<br />
<br />
The following chart found in [http://online.wsj.com/article/SB125511780864976689.html the Wall Street Journal of October 9, 2009] paints a different picture. “New infections occurred in 51 of the 8,197 people who got the vaccine, compared with 74 of the 8,198 volunteers who got placebo shots.” Note that the “125” infections represent “51 + 74.”<br />
<br />
<br />
<center> http://www.dartmouth.edu/~chance/forwiki/HiV.gif</center><br />
<br />
The announcement on September 24, 2009 indicated that the p-value is 3.9%. A Minitab run shows that, in fact, the p-value is higher (i.e., worse) as indicated by the Fisher exact test. However, the .048 is still under the mystical .05:<br />
<br />
'''Test and CI for Two Proportions''' <br />
<br />
<table width="50%" border="1"><br />
<tr> <br />
<td><div align="center">Sample</div></td><br />
<td><div align="center">X</div></td><br />
<td><div align="center">N</div></td><br />
<td><div align="center">Sample p</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">1</div></td><br />
<td><div align="center">51</div></td><br />
<td><div align="center">8197</div></td><br />
<td><div align="center">0.006222</div></td><br />
</tr><br />
<tr> <br />
<td><div align="center">2</div></td><br />
<td><div align="center">74</div></td><br />
<td><div align="center">8198</div></td><br />
<td><div align="center">0.009027</div></td><br />
</tr><br />
</table><br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: -0.00280480<br><br />
95% CI for difference: (-0.00546736, -0.000142249)<br><br />
Test for difference = 0 (vs not = 0): Z = -2.06 P-Value = 0.039<br><br />
<br />
Fisher's exact test: P-Value = 0.048<br><br />
<br />
“Efficacy” of 31.2% seems to be determined from<br><br />
(74 - 51)/ 74 = .310<br><br />
<br />
In the final column of the chart--“Strictly adheres to trial design”--appears the unreleased<br> “per protocol” version. According to<br> [http://blogs.sciencemag.org/scienceinsider/2009/10/unrevealed-anal.html Science Magazine]: <br />
<br />
::The second analysis is called “per protocol” and adheres strictly to how the trial was designed by only including the study participants who got the full regimen of vaccine shots at the right time. Because it excludes study participants who didn't get the full vaccine regimen, it usually provides corroboration to the looser “intent to treat” findings.<br />
<br />
The article doesn’t say what the breakdown of the 86 infections is. Nevertheless, it indicates that the p-value of 16% puts a damper on enthusiasm for the vaccine.<br />
<br />
::The press conference was not a scholarly, rigorously honest presentation,” said one leading HIV/AIDS investigator, who like others asked that his name not be used. “It doesn’t meet the standards that have been set for other trials, and it doesn’t fully present the borderline results. It’s wrong.”<br />
<br />
Discussion<br />
<br />
1. “Strictly adheres to trial design” has an efficacy of 26.2% and 86 infections. Show that this leads approximately to 36 and 50 infections, respectively. <br />
<br />
2. The articles fail to tell us the number of participants in the “per protocol” situation. However, use the 36 and 50 cited above and show via a statistics package such as Minitab that the Fisher exact test comes up with about 16% for the p-value regardless of whether the sample sizes are the original ones or 4000 each, 5000 each, etc.<br />
<br />
3. The “researchers with the U.S. Army who helped run the study, strongly objected to the assertion that they gave the data a positive spin… The debate over the way the results were presented will have no immediate practical impact because even under the most optimistic assessment, the vaccine offered too little protection to be a serious candidate for widespread use.” If this is so, why was there so much positive publicity in September?<br />
<br />
Submitted by Paul Alper<br />
<br />
<blockquote>University of North Dakota researchers found that pilots who ate the fattiest foods such as butter or gravy had the quickest response times in mental tests and made fewer mistakes when flying in tricky cloud conditions.<br></blockquote><br />
<br />
<div align="right">[http://www.startribune.com/lifestyle/health/63619382.html?elr=KArksLckD8EQDUoaEyqyP4O:DW3ckUiD3aPc:_Yyc:aUUl Startribune] <br><br />
Dave Kolpack<br> Associated Press<br><br />
October 6, 2009</div> <br />
<br />
-----<br />
<br />
==Carrying a gun increases risk of getting shot and killed==<br />
[http://www.newscientist.com/article/dn17922-carrying-a-gun-increases-risk-of-getting-shot-and-killed.html The NewScientist]<Br> <br />
October 06 2009 <br><br />
Ewen Callaway<br />
<br />
In this article we read<br />
<blockquote>People who carry guns are far likelier to get shot – and killed – than those who are unarmed, a study of shooting victims in Philadelphia, Pennsylvania, has found. It would be impractical – not to say unethical – to randomly assign volunteers to carry a gun or not and see what happens. So Charles Branas's team at the University of Pennsylvania analyzed 677 shootings over two-and-a-half years to discover whether victims were carrying at the time, and compared them to other Philly residents of similar age, sex and ethnicity. The team also accounted for other potentially confounding differences, such as the socioeconomic status of their neighborhood.</blockquote><br />
Their article will appear in the American Journal of Public Health. The current version of this article can be found [http://www.ajph.org/cgi/reprint/AJPH.2008.143099v1.pdf here] and the most resent abstract can be found [http://www.ajph.org/cgi/content/abstract/AJPH.2008.143099v1 here] in this abstract we read:<br><br><br />
<blockquote>Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.<br><br><br />
Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.<br><br><br />
Results. After adjustment, individuals in possession of a gun were 4.46 (P<.05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P<.05).<br><br><br />
Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.</blockquote><br />
<br />
Discussion<br />
<br />
Why do you think the New Science and other's discussing this study titled there article "Carrying a gun increases risk of getting shot and killed" rather than the title of of the article "Investigating the Link Between Gun Possession and Gun Assault"?<br />
<br />
Of course this is the kind of article that lends iself to interesting comments. For example:<br />
<br />
I am definitely going to have to find the complete article. I want to see how they determined which victims of being shot were included in the study and how they determined which civilians would be included in the study. With out that information, this study doesn't really mean anything.<br />
<br />
Follow this advice and see if you think the study really means anything.<br />
<br />
Sounds to me like a completely ignorant study and weighted to get the result they want. If you check a place like Philidelphia, of course this is the result you would get, because the people carrying guns are more likely to be involved in crimes or living in crime ridden areas. Check Dallas, or Oklahoma City. You wouldn't get that result at all. And that's because dang near everybody has guns, and we have far fewer shootings.<br />
<br />
Does this suggest that the study is completely ignorant?<br />
<br />
This article was suggested by Gordon Fox<br />
<br />
==Identifying financial market cycles - or not==<br />
[http://www.newyorker.com/reporting/2009/10/12/091012fa_fact_paumgarten “The Secret Cycle”], by Nick Paumgarten, <i>The New Yorker</i>, October 12, 2009<br><br />
<br />
This article focuses on the work of Martin Armstrong, a technical financial analyst, who found that, "on average, there had been a panic every 8.6 years" over the period 1683-1907:<br />
<blockquote>He discerned a recurrence of major turning points in the economy and in world affairs that followed a distinct and unwavering 8.6-year rhythm.</blockquote><br />
<br />
Then he found that the October 1987 crash “took place on the minor halfway point up the first leg of the 8.6-year cycle, at 2.15 years,” noting that "8.6 years was exactly … 3,141 [days], the number pi times a thousand.”<br><br />
<br />
Eventually:<br />
<blockquote>The model … failed, among other things, to foresee its developer’s demise. In September, 1999, Armstrong was charged with defrauding Japanese investors of nearly a billion dollars. …. The upshot, though, is that he has now spent more than nine years in jail – a pi cycle and then some.</blockquote><br />
<br />
The article includes discussions of Fibonacci-based market behavior models and the "reasoning" behind them.<br><br />
<br />
Submitted by Margaret Cibes<br />
<br />
==Learning by the petabyte==<br />
<br />
[http://www.nytimes.com/2009/10/12/technology/12data.html Training to Climb an Everest of Digital Data]. Ashlee Vance, The New York Times, October 11, 2009.<br />
<br />
Some Statistics textbooks have been criticized for having small "toy" problems that do not reflect the complexity of data analysis out in the real world. What sort of data sets are out in the real world?<br />
<br />
<blockquote> Facebook, for example, uses more than 1 petabyte of storage space to manage its users’ 40 billion photos. It was not long ago that the notion of one company having anything close to 40 billion photos would have seemed tough to fathom. Google, meanwhile, churns through 20 times that amount of information every single day just running data analysis jobs. In short order, DNA sequencing systems too will generate many petabytes of information a year.</blockquote><br />
<br />
Even at the best universities, students are not asked to handle data sets this large. And this is a problem.<br />
<br />
<blockquote>For the most part, university students have used rather modest computing systems to support their studies. They are learning to collect and manipulate information on personal computers or what are known as clusters, where computer servers are cabled together to form a larger computer. But even these machines fail to churn through enough data to really challenge and train a young mind meant to ponder the mega-scale problems of tomorrow. "If they imprint on these small systems, that becomes their frame of reference and what they’re always thinking about," said Jim Spohrer, a director at I.B.M.'s Almaden Research Center. </blockquote><br />
<br />
Two companies with lots of experience tackling petabyte sized data sets want to change this.<br />
<br />
<blockquote>Two years ago, I.B.M. and Google set out to change the mindset at universities by giving students broad access to some of the largest computers on the planet. The companies then outfitted the computers with software that Internet companies use to tackle their toughest data analysis jobs. And, rather than building a big computer at each university, the companies created a system that let students and researchers tap into giant computers over the Internet. This year, the National Science Foundation, a federal government agency, issued a vote of confidence for the project by splitting $5 million among 14 universities that want to teach their students how to grapple with big data questions.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. What is the size of the largest data set that you have ever analyzed. Did the size of the data set force you to use a different computing system, different software, or a different statistical method?<br />
<br />
2. Could a random sample of a few megabytes from a petabyte of data be sufficiently useful to learn on? Note that a megabyte is six orders of magnitude smaller than a petabyte. Is it possible to have a representative sample with a data set sampled this sparsely?<br />
<br />
3. [http://en.wikipedia.org/wiki/Moore%27s_law Moore's Law] says (more or less) that computing capacity doubles every two years (some sources say 18 months). If Moore's Law applies, calculate how long will it take before we see petabyte sized hard drives on laptop computers?.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_55&diff=9158Chance News 552009-09-26T22:20:07Z<p>PaulAlper: /* Flu Shots */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Populism, in its latest manifestation, celebrates ignorant opinion and undifferentiated rage. .... The typical opinion poll … doesn’t trouble to ask whether the respondent knows the first thing about the topic being opined upon, and no conventional poll disqualifies an answer on the ground of mere total ignorance. The premise of opinion polling is that people are, and of right ought to be, omni-opinionated – that they should have views on all subjects at all times – and that all such views are equally valid. …. So, given the prominence of polls in our political culture, it’s no surprise that people have come to believe that their opinions on the issues of the day need not be fettered by either facts or reflection. …. Now there’s the intellectual free lunch: I’m entitled to vociferous opinions on any subject, without having to know, or even think, about it.</blockquote><br />
<br />
<div align=right>Michael Kinsley, <i>The New Yorker</i>, February 6, 1995</div align=right)><br />
<br />
-----<br />
<blockquote>We live in a world of real dangers and imagined fears. …. We are hounded by what I call “psycho-facts”: beliefs that, though not supported by hard evidence, are taken as real because their constant repetition changes the way we experience life. …. We act as if there’s a constitutional right to immortality and that anything that raises risk should be outlawed. <br />
….</blockquote><br />
<div align=right>Robert J. Samuelson, <i>Newsweek</i>, May 9, 1994</div align=right><br />
<br />
-----<br />
In a September 18 <i>Statesman Journal</i> story, [http://www.statesmanjournal.com/article/20090918/SPORTS/909180329/1001/news “Ducks’ defense faces tough challenge”], a coach was quoted:<br />
<blockquote>The only statistic that counts is winning and losing …. We don't get caught up in that. .... How many yards and those things.</blockquote><br />
<br />
-----<br />
A retiring associate professor of math at BVU was described in a <i>Storm Lake Pilot Tribune</i> article [http://www.zwire.com/site/news.cfm?newsid=20370394&BRD=1304&PAG=461&dept_id=180485&rfi=6]<br />
of September 17:<br />
<blockquote>His love for math outweighed his love of sports by a few percentage points.</blockquote><br />
<br />
-----<br />
<blockquote>The plain fact is that 70 years ago Ronald Fisher gave scientists<br />
a mathematical machine for turning baloney into breakthroughs,<br />
and flukes into funding. It is time to pull the plug.</blockquote><br />
<br />
[http://www2.isye.gatech.edu/~brani/isyebayes/bank/pvalue.pdf Robert Mathews] commenting on medical studies which have a low p-value and thus are statistically significant but subsequently turn out to be duds when expanded to the general population.<br />
<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Forsooths==<br />
<br />
Responding to a Canadian viewer who pointed out that "life expectancy in Canada under our health system is higher than the USA," Fox's Bill O'Reilly on 7/27/09 said, <blockquote>Well, that's to be expected, Peter, because we have 10 times as many people as you do. That translates to 10 times as many accidents, crimes, down the line.</blockquote><br />
<br />
-----<br />
According to a September 18 FOX8 News WVUE-TV story, [http://www.fox8live.com/news/local/story/Chance-for-rain-confusing-or-useful-statistic/qz46lnCXU06SQhmu3szNQA.cspx “Chance for rain”], the following information was published in a cover story in an early 2009 bulletin of the American Meteorological Society:<br />
<blockquote> [Researchers at the University of Washington] found people in Seattle didn't have much of a grasp for what the probability forecast [of rain] really means, but found the numbers helpful in planning their day.</blockquote><br />
<br />
-----<br />
Hanna Karp, in [http://online.wsj.com/article/SB10001424052970204518504574417392008401168.html “What’s the Point of Cheerleading?”], <i>The Wall Street Journal</i>, September 17, 2009, states:<br />
<blockquote>Risk-assessment experts say it’s hard to get a handle on the perils of cheerleading.</blockquote><br />
<br />
-----<br />
An advertisement in <i>The Wall Street Journal</i>, of September 22, 2009, contained a chart with an interesting legend. See the chart “Effectiveness of virtual vs. in-person meetings,” in [http://www.tia.org/resources/PDFs/ROI/9-03-09_Oxford_Economics.pdf “The Return on Investment of U.S. Business Travel”], prepared by Oxford Economics USA, September 2009, document page 21/pdf page 20.<br><br />
Students might find it challenging to describe in one sentence what it says. They also might be asked to re-create the chart so that it would convey the message more effectively, that is, pass the interocular trauma test.<br />
<br />
==Breaking News==<br />
<br />
<i>The Wall Street Journal</i> of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.” <br />
<br />
<table width="77%" border="1"><br />
<tr> <br />
<td width="24%" height="39">Sample</td><br />
<td width="22%"><p align="center">Reoperations </p><br />
<p align="center">Needed</p></td><br />
<td width="25%"><div align="center">Sample Size</div></td><br />
<td width="29%"><div align="center">Sample Proportion</div></td><br />
</tr><br />
<tr> <br />
<td height="42">Outside Normal Hours</td><br />
<td> <div align="center">28</div></td><br />
<td> <div align="center">82</div></td><br />
<td> <p align="center">.3415</p><br />
<td> <div align="center"></div></td><br />
</tr><br />
<td>Within Normal Hours</td><br />
<td> <div align="center">12</div></td><br />
<td> <div align="center">70</div></td><br />
<td> <div align="center">.1714</div></td><br />
</tr><br />
</table><br />
<br />
The results are:<br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.170035<br />
95% CI for difference: (0.0346494, 0.305420)<br />
Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018<br />
<br />
Fisher's exact test: P-Value = 0.026<br />
<br />
Discussion<br />
<br />
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?<br />
<br />
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Amazon River at age 1,000,003 years==<br />
[http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/ “Metrics mania: Are Americans too reliant on numbers?”]<br> <br />
by John Yemma, <i>The Christian Science Monitor</i>, September 16, 2009<br><br />
<br />
The author first reminds readers of an old joke:<br />
<blockquote>A guy strikes up a conversation with another guy on a long plane flight to South America. They are over the Amazon.<br><br />
Guy 1: “Did you know that the Amazon is 1,000,003 years old?”<br><br />
Guy 2: “Really? How can you be so precise?”<br><br />
Guy 1: “I was on this same flight three years ago, and a geologist told me the Amazon was a million years old.”</blockquote><br />
He then discusses the difficulty with “metrics-based management” efforts, but concludes, in a hopeful vein, with a formula and some encouragement:<br />
<blockquote>Metrics + Grain of Salt = Somewhat Useful Information.<br><br />
Still, even if we can’t trust data absolutely, we can extract meaning. We may not know how old the Amazon really is, but we know one thing for certain: It is three years older than when Guy 1 first flew over it.</blockquote><br />
<br />
A blogger comments [http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/], <br />
<blockquote>So true. I am an European who has lived in the US for almost 20 years. I am constantly amazed at the ‘number obsession’ that seems to rule all areas of society. It may be because this country is so big, that a common measure can only be found in quantities, not qualities.</blockquote><br />
<br />
==Gompertz Law of human mortality==<br />
[http://freakonomics.blogs.nytimes.com/2009/09/14/youre-likely-to-live/ “You’re Likely to Live!”]<br><br />
by “Freakonomics,” <i>The New York Times</i>, September 14, 2009<br> <br />
This very brief article describes the “Gompertz Law of human mortality,” provides some statistics about the different chances of dying at different ages, and refers readers to three websites:<br><br />
(a) Article with Gompertz Law details and graphs: [http://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/ “Your body wasn’t built to last: a lesson from human mortality rates”], "gravity and levity" blog, July 8, 2009.<br><br />
(b) Applet that gives life expectancy at user-selected age: [http://forio.com/simulate/simulation/mbean/death-probability-calculator/ “Death Probability Calculator”], undated.<br><br />
(c) TED video of songs, the first of which relates to aging: [http://www.ted.com/talks/they_might_be_giants_play_at_8_30_am.html “Time is marching on”], March 2007.<br><br />
<br />
==Things that go bump==<br />
[http://online.wsj.com/article/SB10001424052970203278404574416813210135226.html “Bumped Passengers Learn a Cruel Flying Lesson”]<br><br />
by Scott McCartney, <i>The Wall Street Journal</i>, September 17, 2009<br><br />
<br />
This article discusses the recent spike in the rates of passenger-bumping by airlines, despite the increased penalties that the federal government requires the airlines to pay bumped-but-ticketed passengers. Although bumping affects fewer than 2 passengers out of every 10,000, that rate rose by 40% in the second quarter of 2009 over the rate for the second quarter of 2008.<br><br />
<blockquote>It's pretty simple: It's just because planes are more full than last year," says [a US Airways official, whose airline] had the highest bumping rate among major airlines, at 1.88 passengers per 10,000 in the second quarter.<br><br />
This summer, the nine major airlines filled 85.5% of their seats, up from 84.1% last summer. The peak was July, with 86.7% of seats filled.</blockquote> <br />
Federal rules allow airlines to overbook in order to compensate for no-shows. The recent increase in bumping rates may be explained by the reduced demand for air travel, especially by business customers.<br />
<blockquote>The [Department of Transportation] says it isn't concerned about the rise in bumping because the rates are still lower than historical highs. During the 1970s and 1980s, bumping rates were routinely four times as high as today's rate.</blockquote><br />
<br />
<b>Discussion</b><br><br />
<br />
Suppose that, on average, 85% of ticket-holders show up for their flights. Assume that the distribution of the number of ticket-holders who show up is binomial (especially that every ticket-holder has the same chance of being bumped) and that a ticket-holder is bumped only due to lack of a seat.<br><br />
<br />
1. For each n tickets sold, or over-sold, for a 200-seat plane, find the number of ticket-holders an airline could expect to show up, on average.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
2. It appears that the airline would not have to bump any ticket-holders for some values of n. Is that a statistically correct inference, based on your understanding of expected value? Even if those expected values always “came true,” what problem would remain for the airline?<br> <br />
<br />
3. For each n tickets sold, or over-sold, find the probability of at least one ticket-holder being bumped off the 200-seat plane.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
4. For which value(s) of n would you have a negligible risk of being bumped? Under what circumstances might any risk be too great?<br><br />
<br />
5. The more tickets an airline sells, the more likely it is to fill the plane and thus maximize its revenue for a flight. However, at some point, the increased revenue may be offset by losses of future dollars from angry ticket-holders and compensation payouts to increasing numbers of bumped ticket-holders. What other information would you want/need to know before deciding how many tickets to sell for a 200-seat plane?<br><br />
<br />
6. Do you agree with the "pretty simple" reason given for the increased rate of bumping?<br />
<br />
==The Bulgarian Toto 6 of 42 lottery== <br />
<br />
The Bulgarian Toto 6 of 42 lottery was the subject of an investigation after the <br />
same set of six numbers {4, 15, 23, 24, 35, 42} was drawn in two successive lotteries on September 6 and September 10, 2009. The article [http://www.novinite.com/view_news.php?id=107914] cites a mathematician as stating that the probability of picking the same six numbers twice in a row is 4,200,000:1. We wondered how he arrived at this number. What is the probability that a specified set of six numbers will repeat consecutively?<br />
<br />
There are <math>{42 \choose 6} = 5245786</math> different sets of six numbers and the probability that a SPECIFIED set will occur in the next two consecutive draws is <math>1/5245786^2</math>. Because the sets involve disjoint events, the probability that SOME set will occur in the next two consecutive draws is <math>5245786 \times 1/5245786^2 = 1/5245786</math>. <br />
<br />
But now, suppose the lottery has been running continuously for <math>m</math> draws and we ask what the chance is that during this period there were consecutive draws of the same set. As before, first consider a fixed set of six numbers.<br />
<br />
There are <math>m-1</math> opportunities for this set to be drawn twice in succession (beginning with the second drawing). The probability that this will happen is then the probability of the union <math>P(A) = P(\cup_i A_i A_{i+1}) </math> where <math>A_i</math> is the event that this set of numbers is drawn on the ith draw.<br />
<br />
Bonferroni's first degree upper bound is <math>P(A) \le \sum_{1 \le i \le m-1} P(A_i A_{i+1})</math> while the second degree lower bound is<br />
<math>P(A) \ge \sum_{1 \le i \le m-1}P(A_i A_{i+1}) - \sum_{1 \le i < j \le m-1}P(A_i A_{i+1} A_j A_{j+1}).</math><br />
<br />
We assume (!) that the events <math>A_i</math> are independent and identically distributed with probability <math>p = 1/5245786</math>. As long as <br />
<math>mp</math> is small the second sum in the lower bound can be ignored, giving <math>P(A) \approx (m-1)/5245786^2.</math><br />
<br />
It appears that the draws are held twice per week so for one year <math>m = 104</math> giving the probability <math>3.74 \times 10^{-12}</math> that a specified set of numbers will be drawn twice in succession. According to a spokeswoman the lottery has been taking place for 52 years<br />
[http://www.canada.com/Bulgaria+identical+lottery+draw+just+coincidence/2003980/story.html?id=2003980x]. <br />
Using <math>m = 104 \times 52 = 5408</math>, the probability that a specified set of numbers will be drawn twice in succession over this period is <math>1.89 \times 10^{-10}</math>, still very small.<br />
<br />
But now let's ask the question, not for a fixed set of numbers but for some set of numbers. After all, in discussing this coincidence the repeated set arises by chance alone and is not specified in advance.<br />
<br />
In <math>m</math> drawings what is the probability that SOME set of six numbers will be repeated in consecutive draws?<br />
<br />
There are 5245786 possible sets of numbers that could be repeated. Enumerate the sets by integers <br />
<math>1 \le k ≤ \le 5245786</math> with <math>E_k</math> the event that set <math>k</math> repeats consecutively sometime during <br />
these <math>m</math> drawings. The probability of the union <math>P(\cup E_k)</math> is needed. Each of the 5245786 events <br />
<math>E_k</math> has probability <math>(m-1)/ 5245786^2</math> and if they were independent we could evaluate the probability using complements as <br />
<math>P(\cup E_k) = 1 - (1- (m-1)/5245786^2)^{5245786} \approx 1 - e^{-(m-1)/5245786}</math>. However, they are dependent, but as long as <math>mp</math> is small Bonferroni's bounds can once again be used to estimate <br />
<math>P(\cup E_k) \approx (m-1)/5245786.</math> For <math>m = 5408</math> this is 0.0010302. (Note that assuming independence gives 0.0010307.)<br />
<br />
This probability relates to one lottery. Suppose we consider all lotteries worldwise and ask for the probability that in some lottery, somewhere, some set of numbers will be repeated consecutively. All lotteries are variants of Toto with different numbers involved. Each lottery will have had its own cumulative number of drawings. In order to gauge the magnitude of the probability wanted, assume that there are <math>x</math> lotteries, each one sharing the same numerical characteristics as the Bulgarian one.<br />
<br />
This time we can use independence. The probability that some set will be repeated is 1 minus the probability that in no lottery is a set of numbers selected on two consecutive drawings <br />
<math>= 1 - (1 - (m -1)/5245786)^x</math>. For <math>x = 50</math> this is 0.0503 while for <math>x = 100</math> the probability is 0.0980. (An approximation to one significant digit for this range of values of interest is <math>x(m-1)/5245786.</math>)<br />
<br />
For a different problem that discusses "very big numbers" see the article about double lottery winners [http://www.nytimes.com/1990/02/27/science/1-in-a-trillion-coincidence-you-say-not-really-experts-find.html?pagewanted=all].<br />
<br />
Questions.<br />
<br />
1. Can you verify both assertions concerning the Bonferroni lower bound.<br />
<br />
2. How many years would the Bulgarian lottery need to be running in order to have the same probability that some set of numbers will appear three times in succession?<br />
<br />
3. Instead of demanding that the same set of numbers appear twice in succession, what is the probability that some set of numbers will repeat during <math>m</math> drawings? (This is simpler and is the famous birthday problem)<br />
<br />
Submitted by Fred Hoppe<br />
<br />
==Baby, it’s cold outside==<br />
[http://online.wsj.com/article/SB125356566517528879.html “New Light on the Plight of Winter Babies”]<br><br />
by Justin Lahart, <i>The Wall Street Journal</i>, September 22, 2009<br><br />
<br />
Two Notre Dame economists “may have uncovered an overlooked explanation for why season of birth matters” with respect to the often reported poor test results, less healthiness, reduced longevity, and lower school completion rates and earnings of children born in the winter. See [http://www.nd.edu/~dhungerm/w14573.pdf “Season of Birth and Later Outcomes: Old Questions, New Answers”], by Kasey Buckles and Daniel Hungerman, National Bureau of Economic Research, December 2008.<br><br />
<br />
Working independently, Hungerman found that “children in the same families tend to be born at the same time of year,” and Buckles found a “tendency that less educated mothers were having children in winter.” They put their heads together and concluded that:<br />
<br />
<blockquote>A key assumption of much of [the previous] research is that the backgrounds of children born in the winter are the same as the backgrounds of children born at other times of the year.</blockquote><br />
<br />
Some previous explanations for seasonal birth differences were school attendance laws, the amount of sunshine available in a season, or the level of pesticides in the water in a season. With respect to the first explanation, economists Joshua Angrist of MIT and Alan Krueger of Princeton posited in 1991 that, since winter babies can drop out of school earlier because they reach their 16th birthdays earlier, those babies have lower education levels that, in turn, lead to lower earnings.<br><br />
<br />
Upon examination of CDC birth-certificate data for virtually all 52 million children born during the period 1989-2001, the Notre Dame researchers noted:<br />
<br />
<blockquote>The percentage of children born to unwed mothers, teenage mothers and mothers who hadn't completed high school kept peaking in January every year. Over the 13-year period, for example, 13.2% of January births were to teen mothers, compared with 12% in May -- a small but statistically significant difference, they say.</blockquote><br />
<br />
A Columbia University economist comments about how striking the Notre Dame results are: "You can take a look at those graphs and see the clear pattern and that it's remarkably stable over time." See graphs [http://online.wsj.com/article/SB125356566517528879.html] of January and May births with respect to birth mother’s marital status, age, and education.<br><br />
<br />
Angrist disagrees, stating "The bottom line is a slight change in the estimate. …. It hardly overturns our finding."<br><br />
<br />
Buckles and Hungerman are now working on finding an explanation of why a mother’s socioeconomic status is related to a child’s birth month.<br> <br />
<br />
(As of September 24, there were 298 blogs [http://online.wsj.com/article/SB125356566517528879.html#articleTabs%3Dcomments] responding to this article!)<br />
<br />
==U.S. Census: 2008 sampling results released==<br />
The U.S. Census Bureau has released the 2008 results of its ongoing [http://www.census.gov/acs/www/ "American Community Survey"].<br />
<br />
==Tennis challenges are underused==<br />
<br />
[http://www.nytimes.com/2009/09/21/opinion/21kedrosky.html Challenge, Anyone?] Paul Kedrosky, The New York Times, September 20, 2009<br />
<br />
It seems like economists have an opinion about just about everything. Paul Kedrosky, described in the New York Times as "senior fellow at the Kauffman Foundation, a center for economic research," has advice for professional tennis players. Challenge the line judges more often.<br />
<br />
Like in American football, tennis players can challenge a judges ruling.<br />
<br />
<blockquote>Here’s how challenges work. Major tennis tournaments (like the U.S. Open) have multiple cameras arrayed around the court. This permits a simulated replay of a shot, showing to the millimeter where a ball landed on the court. So instead of futilely shouting, "You can't be serious!" at linesmen and umpires, players can raise their hand immediately after a call and ask for a replay.</blockquote><br />
<br />
There are limits to how often you can challenge.<br />
<br />
<blockquote>The rules allow three incorrect challenges per player per set. In a best-of-five-sets match (which is normal for men), that means at least 18 available challenges per match, none of which carry over from set to set.In other words, use ’em or lose ’em. A player can get an additional challenge if the match goes into a tiebreaker, or if a fifth set goes overtime.</blockquote><br />
<br />
But most tennis players don't come even close to using all of their available challenges. And they should according to Kedrosky. Here's one scenario he proposes:<br />
<br />
<blockquote>For example, the No. 10 seed at the Open, Fernando Verdasco of Spain, averaged 0.4 challenges per set and had a sparkling 43 percent success rate. If he challenged once per set, like Federer, and his challenge success rate fell to a similar 30 percent, it could mean one more point to him in a three-set match. If his success rate didn’t fall as much, however, and he challenged twice per set it might mean as many as three more points in a five-set match. Either way, it could be the difference between winning and losing.</blockquote><br />
<br />
There are other factors at work, such as embarrassment when a challenge does not go your way, but Kedrosky thinks players should ignore this.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Suppose you wanted to run a computer simulation about close calls in tennis and vary the rate at which players challenge close calls. What are some of the rnadom variables that you would have to account for in such a simulation?<br />
<br />
2. How much of an edge would one more point mean in a match between two players who are otherwise evenly matched?<br />
<br />
==Netflix data mining contest==<br />
<br />
[http://www.nytimes.com/2009/09/22/technology/internet/22netflix.html A $1 Million Research Bargain for Netflix, and Maybe a Model for Others] Steve Lohr, The New York Times, September 21, 2009.<br />
<br />
[http://bits.blogs.nytimes.com/2009/09/21/netflix-awards-1-million-prize-and-starts-a-new-contest Netflix Awards $1 Million Prize and Starts a New Contest] Steve Lohr, Bits Blog, The New York Times, September 21, 2009.<br />
<br />
Netflix just awarded a million dollar prize in a contest to build a data mining model that could predict what movies its customers would like to see. There was a tight competition between two teams. The winning team, BellKor’s Pragmatic Chaos, was a group of seven "statisticians, machine-learning experts and computer engineers from the United States, Austria, Canada and Israel". The second place team, Ensemble, was "a global alliance with some 30 members."<br />
<br />
<blockquote>The losing team, as it turned out, precisely matched the performance of the winner, but submitted its entry 20 minutes later, just before the final deadline expired. Under contest rules, in the event of a tie, the first team past the post was the winner. “That 20 minutes was worth a million dollars,” Reed Hastings, chief executive of Netflix, said at a news conference in New York.</blockquote><br />
<br />
Netflix has already improved its system to help customers pick movies and thinks the million dollar investment was well spent.<br />
<br />
<blockquote>Thousands of teams from more than 100 nations competed in the Netflix prize contest. And it was a good deal for Netflix. “You look at the cumulative hours and you’re getting Ph.D.’s for a dollar an hour,” Mr. Hastings said in an interview.</blockquote><br />
<br />
The losing team was not too upset.<br />
<br />
<blockquote>Yet the scientists and engineers on the second-place team, and the employers who gave many of them the time and freedom to compete in the contest, were hardly despairing. Arnab Gupta, chief executive of Opera Solutions, a consulting company that specializes in data analytics, based in New York, took a small group of his leading researchers off other work for two years. "We've already had a $10 million payoff internally from what we’ve learned," Mr. Gupta said. Working on the contest helped the researchers come up with improved statistical analysis and predictive modeling techniques that his firm has used with clients in fields like marketing, retailing and finance, he said. "So for us, the $1 million prize was secondary, almost trivial."</blockquote><br />
<br />
The data set itself was the true prize to many team members.<br />
<br />
<blockquote>Win or lose, researchers agreed that they entered the contest in good part to get access to the Netflix data. "It was incredibly alluring to work on such a large, high-quality data set," said Joe Sill, an independent consultant and machine-learning expert who was a member of the Ensemble.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
==Flu Shots==<br />
<br />
The Wall Street Journal of September 24, 2009 reports on a study in the current issue of the New England Journal of Medicine dealing with the efficacy of flu shots during the “2007-2008 flu season.” There were “1952 healthy adults who received either a placebo or one of two [types of] vaccinations,” either a shot or a spray. <br />
<br />
“Of the 813 volunteers who received the flu shot, 28 of them or 3.4%, later developed a confirmed case of influenza. In the FluMist group; 56 of the 814 volunteers, or 6.9% developed the flu, while 10.8% of the placebo group had confirmed flu cases.”<br />
<br />
Discussion<br />
<br />
1. Here is the Minitab output for the comparison between the two forms of vaccination:<br />
<br />
Test and CI for Two Proportions <br />
<br />
<table width="50%" border="1"><br />
<tr><br />
<td>Sample</td><br />
<td>X</td><br />
<td>N</td><br />
<td>Sample p</td><br />
</tr><br />
<tr><br />
<td>1</td><br />
<td>56</td><br />
<td>814</td><br />
<td>0.068796</td><br />
</tr><br />
<tr><br />
<td>2</td><br />
<td>28</td><br />
<td>813</td><br />
<td>0.034440</td><br />
</tr><br />
</table><br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.0343557<br><br />
95% CI for difference: (0.0129208, 0.0557907)<br><br />
Test for difference = 0 (vs not = 0): Z = 3.14 P-Value = 0.002<br />
<br />
Fisher's exact test: P-Value = 0.002<br />
<br />
How does this output support the conclusion that the shot works better than the spray?<br />
<br />
2. Because the number of volunteers is 1952 and the total number in the control arms is 1627 (814 + 813), the number of volunteers who received the placebo is 325. Below is the Minitab output comparing the controls vs. the placebo:<br />
<br />
Test and CI for Two Proportions <br />
<br />
<table width="50%" border="1"><br />
<tr><br />
<td>Sample</td><br />
<td>X</td><br />
<td>N</td><br />
<td>Sample p</td><br />
</tr><br />
<tr><br />
<td>1</td><br />
<td>35</td><br />
<td>325</td><br />
<td>0.107692</td><br />
</tr><br />
<tr><br />
<td>2</td><br />
<td>84</td><br />
<td>1627</td><br />
<td>0.051629</td><br />
</tr><br />
</table><br />
<br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.0560635<br><br />
95% CI for difference: (0.0206880, 0.0914391<br><br />
Test for difference = 0 (vs not = 0): Z = 3.86 P-Value = 0.000<br />
<br />
Fisher's exact test: P-Value = 0.000<br />
<br />
How does this support the conclusion that the vaccinations work better than the placebo?<br />
<br />
3. According to the article, the makers of the shot, Sanofi Pasteur, “provided funding for the study” and the lead author “reports receiving lecture fees from the company.” No mention is made of MedImmune Inc., makers of the spray. How does this modify your conclusions?<br />
<br />
4. Roughly 5% (84 of 1627) of those who received a vaccination still became confirmed flu victims. Find a friendly librarian to determine how this compares with vaccinations for other diseases such as measles, mumps, rubella, chicken pox and shingles.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_55&diff=9157Chance News 552009-09-26T20:23:24Z<p>PaulAlper: /* Flu Shots */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Populism, in its latest manifestation, celebrates ignorant opinion and undifferentiated rage. .... The typical opinion poll … doesn’t trouble to ask whether the respondent knows the first thing about the topic being opined upon, and no conventional poll disqualifies an answer on the ground of mere total ignorance. The premise of opinion polling is that people are, and of right ought to be, omni-opinionated – that they should have views on all subjects at all times – and that all such views are equally valid. …. So, given the prominence of polls in our political culture, it’s no surprise that people have come to believe that their opinions on the issues of the day need not be fettered by either facts or reflection. …. Now there’s the intellectual free lunch: I’m entitled to vociferous opinions on any subject, without having to know, or even think, about it.</blockquote><br />
<br />
<div align=right>Michael Kinsley, <i>The New Yorker</i>, February 6, 1995</div align=right)><br />
<br />
-----<br />
<blockquote>We live in a world of real dangers and imagined fears. …. We are hounded by what I call “psycho-facts”: beliefs that, though not supported by hard evidence, are taken as real because their constant repetition changes the way we experience life. …. We act as if there’s a constitutional right to immortality and that anything that raises risk should be outlawed. <br />
….</blockquote><br />
<div align=right>Robert J. Samuelson, <i>Newsweek</i>, May 9, 1994</div align=right><br />
<br />
-----<br />
In a September 18 <i>Statesman Journal</i> story, [http://www.statesmanjournal.com/article/20090918/SPORTS/909180329/1001/news “Ducks’ defense faces tough challenge”], a coach was quoted:<br />
<blockquote>The only statistic that counts is winning and losing …. We don't get caught up in that. .... How many yards and those things.</blockquote><br />
<br />
-----<br />
A retiring associate professor of math at BVU was described in a <i>Storm Lake Pilot Tribune</i> article [http://www.zwire.com/site/news.cfm?newsid=20370394&BRD=1304&PAG=461&dept_id=180485&rfi=6]<br />
of September 17:<br />
<blockquote>His love for math outweighed his love of sports by a few percentage points.</blockquote><br />
<br />
-----<br />
<blockquote>The plain fact is that 70 years ago Ronald Fisher gave scientists<br />
a mathematical machine for turning baloney into breakthroughs,<br />
and flukes into funding. It is time to pull the plug.</blockquote><br />
<br />
[http://www2.isye.gatech.edu/~brani/isyebayes/bank/pvalue.pdf Robert Mathews] commenting on medical studies which have a low p-value and thus are statistically significant but subsequently turn out to be duds when expanded to the general population.<br />
<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Forsooths==<br />
<br />
Responding to a Canadian viewer who pointed out that "life expectancy in Canada under our health system is higher than the USA," Fox's Bill O'Reilly on 7/27/09 said, <blockquote>Well, that's to be expected, Peter, because we have 10 times as many people as you do. That translates to 10 times as many accidents, crimes, down the line.</blockquote><br />
<br />
-----<br />
According to a September 18 FOX8 News WVUE-TV story, [http://www.fox8live.com/news/local/story/Chance-for-rain-confusing-or-useful-statistic/qz46lnCXU06SQhmu3szNQA.cspx “Chance for rain”], the following information was published in a cover story in an early 2009 bulletin of the American Meteorological Society:<br />
<blockquote> [Researchers at the University of Washington] found people in Seattle didn't have much of a grasp for what the probability forecast [of rain] really means, but found the numbers helpful in planning their day.</blockquote><br />
<br />
-----<br />
Hanna Karp, in [http://online.wsj.com/article/SB10001424052970204518504574417392008401168.html “What’s the Point of Cheerleading?”], <i>The Wall Street Journal</i>, September 17, 2009, states:<br />
<blockquote>Risk-assessment experts say it’s hard to get a handle on the perils of cheerleading.</blockquote><br />
<br />
-----<br />
An advertisement in <i>The Wall Street Journal</i>, of September 22, 2009, contained a chart with an interesting legend. See the chart “Effectiveness of virtual vs. in-person meetings,” in [http://www.tia.org/resources/PDFs/ROI/9-03-09_Oxford_Economics.pdf “The Return on Investment of U.S. Business Travel”], prepared by Oxford Economics USA, September 2009, document page 21/pdf page 20.<br><br />
Students might find it challenging to describe in one sentence what it says. They also might be asked to re-create the chart so that it would convey the message more effectively, that is, pass the interocular trauma test.<br />
<br />
==Breaking News==<br />
<br />
<i>The Wall Street Journal</i> of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.” <br />
<br />
<table width="77%" border="1"><br />
<tr> <br />
<td width="24%" height="39">Sample</td><br />
<td width="22%"><p align="center">Reoperations </p><br />
<p align="center">Needed</p></td><br />
<td width="25%"><div align="center">Sample Size</div></td><br />
<td width="29%"><div align="center">Sample Proportion</div></td><br />
</tr><br />
<tr> <br />
<td height="42">Outside Normal Hours</td><br />
<td> <div align="center">28</div></td><br />
<td> <div align="center">82</div></td><br />
<td> <p align="center">.3415</p><br />
<td> <div align="center"></div></td><br />
</tr><br />
<td>Within Normal Hours</td><br />
<td> <div align="center">12</div></td><br />
<td> <div align="center">70</div></td><br />
<td> <div align="center">.1714</div></td><br />
</tr><br />
</table><br />
<br />
The results are:<br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.170035<br />
95% CI for difference: (0.0346494, 0.305420)<br />
Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018<br />
<br />
Fisher's exact test: P-Value = 0.026<br />
<br />
Discussion<br />
<br />
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?<br />
<br />
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Amazon River at age 1,000,003 years==<br />
[http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/ “Metrics mania: Are Americans too reliant on numbers?”]<br> <br />
by John Yemma, <i>The Christian Science Monitor</i>, September 16, 2009<br><br />
<br />
The author first reminds readers of an old joke:<br />
<blockquote>A guy strikes up a conversation with another guy on a long plane flight to South America. They are over the Amazon.<br><br />
Guy 1: “Did you know that the Amazon is 1,000,003 years old?”<br><br />
Guy 2: “Really? How can you be so precise?”<br><br />
Guy 1: “I was on this same flight three years ago, and a geologist told me the Amazon was a million years old.”</blockquote><br />
He then discusses the difficulty with “metrics-based management” efforts, but concludes, in a hopeful vein, with a formula and some encouragement:<br />
<blockquote>Metrics + Grain of Salt = Somewhat Useful Information.<br><br />
Still, even if we can’t trust data absolutely, we can extract meaning. We may not know how old the Amazon really is, but we know one thing for certain: It is three years older than when Guy 1 first flew over it.</blockquote><br />
<br />
A blogger comments [http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/], <br />
<blockquote>So true. I am an European who has lived in the US for almost 20 years. I am constantly amazed at the ‘number obsession’ that seems to rule all areas of society. It may be because this country is so big, that a common measure can only be found in quantities, not qualities.</blockquote><br />
<br />
==Gompertz Law of human mortality==<br />
[http://freakonomics.blogs.nytimes.com/2009/09/14/youre-likely-to-live/ “You’re Likely to Live!”]<br><br />
by “Freakonomics,” <i>The New York Times</i>, September 14, 2009<br> <br />
This very brief article describes the “Gompertz Law of human mortality,” provides some statistics about the different chances of dying at different ages, and refers readers to three websites:<br><br />
(a) Article with Gompertz Law details and graphs: [http://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/ “Your body wasn’t built to last: a lesson from human mortality rates”], "gravity and levity" blog, July 8, 2009.<br><br />
(b) Applet that gives life expectancy at user-selected age: [http://forio.com/simulate/simulation/mbean/death-probability-calculator/ “Death Probability Calculator”], undated.<br><br />
(c) TED video of songs, the first of which relates to aging: [http://www.ted.com/talks/they_might_be_giants_play_at_8_30_am.html “Time is marching on”], March 2007.<br><br />
<br />
==Things that go bump==<br />
[http://online.wsj.com/article/SB10001424052970203278404574416813210135226.html “Bumped Passengers Learn a Cruel Flying Lesson”]<br><br />
by Scott McCartney, <i>The Wall Street Journal</i>, September 17, 2009<br><br />
<br />
This article discusses the recent spike in the rates of passenger-bumping by airlines, despite the increased penalties that the federal government requires the airlines to pay bumped-but-ticketed passengers. Although bumping affects fewer than 2 passengers out of every 10,000, that rate rose by 40% in the second quarter of 2009 over the rate for the second quarter of 2008.<br><br />
<blockquote>It's pretty simple: It's just because planes are more full than last year," says [a US Airways official, whose airline] had the highest bumping rate among major airlines, at 1.88 passengers per 10,000 in the second quarter.<br><br />
This summer, the nine major airlines filled 85.5% of their seats, up from 84.1% last summer. The peak was July, with 86.7% of seats filled.</blockquote> <br />
Federal rules allow airlines to overbook in order to compensate for no-shows. The recent increase in bumping rates may be explained by the reduced demand for air travel, especially by business customers.<br />
<blockquote>The [Department of Transportation] says it isn't concerned about the rise in bumping because the rates are still lower than historical highs. During the 1970s and 1980s, bumping rates were routinely four times as high as today's rate.</blockquote><br />
<br />
<b>Discussion</b><br><br />
<br />
Suppose that, on average, 85% of ticket-holders show up for their flights. Assume that the distribution of the number of ticket-holders who show up is binomial (especially that every ticket-holder has the same chance of being bumped) and that a ticket-holder is bumped only due to lack of a seat.<br><br />
<br />
1. For each n tickets sold, or over-sold, for a 200-seat plane, find the number of ticket-holders an airline could expect to show up, on average.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
2. It appears that the airline would not have to bump any ticket-holders for some values of n. Is that a statistically correct inference, based on your understanding of expected value? Even if those expected values always “came true,” what problem would remain for the airline?<br> <br />
<br />
3. For each n tickets sold, or over-sold, find the probability of at least one ticket-holder being bumped off the 200-seat plane.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
4. For which value(s) of n would you have a negligible risk of being bumped? Under what circumstances might any risk be too great?<br><br />
<br />
5. The more tickets an airline sells, the more likely it is to fill the plane and thus maximize its revenue for a flight. However, at some point, the increased revenue may be offset by losses of future dollars from angry ticket-holders and compensation payouts to increasing numbers of bumped ticket-holders. What other information would you want/need to know before deciding how many tickets to sell for a 200-seat plane?<br><br />
<br />
6. Do you agree with the "pretty simple" reason given for the increased rate of bumping?<br />
<br />
==The Bulgarian Toto 6 of 42 lottery== <br />
<br />
The Bulgarian Toto 6 of 42 lottery was the subject of an investigation after the <br />
same set of six numbers {4, 15, 23, 24, 35, 42} was drawn in two successive lotteries on September 6 and September 10, 2009. The article [http://www.novinite.com/view_news.php?id=107914] cites a mathematician as stating that the probability of picking the same six numbers twice in a row is 4,200,000:1. We wondered how he arrived at this number. What is the probability that a specified set of six numbers will repeat consecutively?<br />
<br />
There are <math>{42 \choose 6} = 5245786</math> different sets of six numbers and the probability that a SPECIFIED set will occur in the next two consecutive draws is <math>1/5245786^2</math>. Because the sets involve disjoint events, the probability that SOME set will occur in the next two consecutive draws is <math>5245786 \times 1/5245786^2 = 1/5245786</math>. <br />
<br />
But now, suppose the lottery has been running continuously for <math>m</math> draws and we ask what the chance is that during this period there were consecutive draws of the same set. As before, first consider a fixed set of six numbers.<br />
<br />
There are <math>m-1</math> opportunities for this set to be drawn twice in succession (beginning with the second drawing). The probability that this will happen is then the probability of the union <math>P(A) = P(\cup_i A_i A_{i+1}) </math> where <math>A_i</math> is the event that this set of numbers is drawn on the ith draw.<br />
<br />
Bonferroni's first degree upper bound is <math>P(A) \le \sum_{1 \le i \le m-1} P(A_i A_{i+1})</math> while the second degree lower bound is<br />
<math>P(A) \ge \sum_{1 \le i \le m-1}P(A_i A_{i+1}) - \sum_{1 \le i < j \le m-1}P(A_i A_{i+1} A_j A_{j+1}).</math><br />
<br />
We assume (!) that the events <math>A_i</math> are independent and identically distributed with probability <math>p = 1/5245786</math>. As long as <br />
<math>mp</math> is small the second sum in the lower bound can be ignored, giving <math>P(A) \approx (m-1)/5245786^2.</math><br />
<br />
It appears that the draws are held twice per week so for one year <math>m = 104</math> giving the probability <math>3.74 \times 10^{-12}</math> that a specified set of numbers will be drawn twice in succession. According to a spokeswoman the lottery has been taking place for 52 years<br />
[http://www.canada.com/Bulgaria+identical+lottery+draw+just+coincidence/2003980/story.html?id=2003980x]. <br />
Using <math>m = 104 \times 52 = 5408</math>, the probability that a specified set of numbers will be drawn twice in succession over this period is <math>1.89 \times 10^{-10}</math>, still very small.<br />
<br />
But now let's ask the question, not for a fixed set of numbers but for some set of numbers. After all, in discussing this coincidence the repeated set arises by chance alone and is not specified in advance.<br />
<br />
In <math>m</math> drawings what is the probability that SOME set of six numbers will be repeated in consecutive draws?<br />
<br />
There are 5245786 possible sets of numbers that could be repeated. Enumerate the sets by integers <br />
<math>1 \le k ≤ \le 5245786</math> with <math>E_k</math> the event that set <math>k</math> repeats consecutively sometime during <br />
these <math>m</math> drawings. The probability of the union <math>P(\cup E_k)</math> is needed. Each of the 5245786 events <br />
<math>E_k</math> has probability <math>(m-1)/ 5245786^2</math> and if they were independent we could evaluate the probability using complements as <br />
<math>P(\cup E_k) = 1 - (1- (m-1)/5245786^2)^{5245786} \approx 1 - e^{-(m-1)/5245786}</math>. However, they are dependent, but as long as <math>mp</math> is small Bonferroni's bounds can once again be used to estimate <br />
<math>P(\cup E_k) \approx (m-1)/5245786.</math> For <math>m = 5408</math> this is 0.0010302. (Note that assuming independence gives 0.0010307.)<br />
<br />
This probability relates to one lottery. Suppose we consider all lotteries worldwise and ask for the probability that in some lottery, somewhere, some set of numbers will be repeated consecutively. All lotteries are variants of Toto with different numbers involved. Each lottery will have had its own cumulative number of drawings. In order to gauge the magnitude of the probability wanted, assume that there are <math>x</math> lotteries, each one sharing the same numerical characteristics as the Bulgarian one.<br />
<br />
This time we can use independence. The probability that some set will be repeated is 1 minus the probability that in no lottery is a set of numbers selected on two consecutive drawings <br />
<math>= 1 - (1 - (m -1)/5245786)^x</math>. For <math>x = 50</math> this is 0.0503 while for <math>x = 100</math> the probability is 0.0980. (An approximation to one significant digit for this range of values of interest is <math>x(m-1)/5245786.</math>)<br />
<br />
For a different problem that discusses "very big numbers" see the article about double lottery winners [http://www.nytimes.com/1990/02/27/science/1-in-a-trillion-coincidence-you-say-not-really-experts-find.html?pagewanted=all].<br />
<br />
Questions.<br />
<br />
1. Can you verify both assertions concerning the Bonferroni lower bound.<br />
<br />
2. How many years would the Bulgarian lottery need to be running in order to have the same probability that some set of numbers will appear three times in succession?<br />
<br />
3. Instead of demanding that the same set of numbers appear twice in succession, what is the probability that some set of numbers will repeat during <math>m</math> drawings? (This is simpler and is the famous birthday problem)<br />
<br />
Submitted by Fred Hoppe<br />
<br />
==Baby, it’s cold outside==<br />
[http://online.wsj.com/article/SB125356566517528879.html “New Light on the Plight of Winter Babies”]<br><br />
by Justin Lahart, <i>The Wall Street Journal</i>, September 22, 2009<br><br />
<br />
Two Notre Dame economists “may have uncovered an overlooked explanation for why season of birth matters” with respect to the often reported poor test results, less healthiness, reduced longevity, and lower school completion rates and earnings of children born in the winter. See [http://www.nd.edu/~dhungerm/w14573.pdf “Season of Birth and Later Outcomes: Old Questions, New Answers”], by Kasey Buckles and Daniel Hungerman, National Bureau of Economic Research, December 2008.<br><br />
<br />
Working independently, Hungerman found that “children in the same families tend to be born at the same time of year,” and Buckles found a “tendency that less educated mothers were having children in winter.” They put their heads together and concluded that:<br />
<br />
<blockquote>A key assumption of much of [the previous] research is that the backgrounds of children born in the winter are the same as the backgrounds of children born at other times of the year.</blockquote><br />
<br />
Some previous explanations for seasonal birth differences were school attendance laws, the amount of sunshine available in a season, or the level of pesticides in the water in a season. With respect to the first explanation, economists Joshua Angrist of MIT and Alan Krueger of Princeton posited in 1991 that, since winter babies can drop out of school earlier because they reach their 16th birthdays earlier, those babies have lower education levels that, in turn, lead to lower earnings.<br><br />
<br />
Upon examination of CDC birth-certificate data for virtually all 52 million children born during the period 1989-2001, the Notre Dame researchers noted:<br />
<br />
<blockquote>The percentage of children born to unwed mothers, teenage mothers and mothers who hadn't completed high school kept peaking in January every year. Over the 13-year period, for example, 13.2% of January births were to teen mothers, compared with 12% in May -- a small but statistically significant difference, they say.</blockquote><br />
<br />
A Columbia University economist comments about how striking the Notre Dame results are: "You can take a look at those graphs and see the clear pattern and that it's remarkably stable over time." See graphs [http://online.wsj.com/article/SB125356566517528879.html] of January and May births with respect to birth mother’s marital status, age, and education.<br><br />
<br />
Angrist disagrees, stating "The bottom line is a slight change in the estimate. …. It hardly overturns our finding."<br><br />
<br />
Buckles and Hungerman are now working on finding an explanation of why a mother’s socioeconomic status is related to a child’s birth month.<br> <br />
<br />
(As of September 24, there were 298 blogs [http://online.wsj.com/article/SB125356566517528879.html#articleTabs%3Dcomments] responding to this article!)<br />
<br />
==U.S. Census: 2008 sampling results released==<br />
The U.S. Census Bureau has released the 2008 results of its ongoing [http://www.census.gov/acs/www/ "American Community Survey"].<br />
<br />
==Tennis challenges are underused==<br />
<br />
[http://www.nytimes.com/2009/09/21/opinion/21kedrosky.html Challenge, Anyone?] Paul Kedrosky, The New York Times, September 20, 2009<br />
<br />
It seems like economists have an opinion about just about everything. Paul Kedrosky, described in the New York Times as "senior fellow at the Kauffman Foundation, a center for economic research," has advice for professional tennis players. Challenge the line judges more often.<br />
<br />
Like in American football, tennis players can challenge a judges ruling.<br />
<br />
<blockquote>Here’s how challenges work. Major tennis tournaments (like the U.S. Open) have multiple cameras arrayed around the court. This permits a simulated replay of a shot, showing to the millimeter where a ball landed on the court. So instead of futilely shouting, "You can't be serious!" at linesmen and umpires, players can raise their hand immediately after a call and ask for a replay.</blockquote><br />
<br />
There are limits to how often you can challenge.<br />
<br />
<blockquote>The rules allow three incorrect challenges per player per set. In a best-of-five-sets match (which is normal for men), that means at least 18 available challenges per match, none of which carry over from set to set.In other words, use ’em or lose ’em. A player can get an additional challenge if the match goes into a tiebreaker, or if a fifth set goes overtime.</blockquote><br />
<br />
But most tennis players don't come even close to using all of their available challenges. And they should according to Kedrosky. Here's one scenario he proposes:<br />
<br />
<blockquote>For example, the No. 10 seed at the Open, Fernando Verdasco of Spain, averaged 0.4 challenges per set and had a sparkling 43 percent success rate. If he challenged once per set, like Federer, and his challenge success rate fell to a similar 30 percent, it could mean one more point to him in a three-set match. If his success rate didn’t fall as much, however, and he challenged twice per set it might mean as many as three more points in a five-set match. Either way, it could be the difference between winning and losing.</blockquote><br />
<br />
There are other factors at work, such as embarrassment when a challenge does not go your way, but Kedrosky thinks players should ignore this.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Suppose you wanted to run a computer simulation about close calls in tennis and vary the rate at which players challenge close calls. What are some of the rnadom variables that you would have to account for in such a simulation?<br />
<br />
2. How much of an edge would one more point mean in a match between two players who are otherwise evenly matched?<br />
<br />
==Netflix data mining contest==<br />
<br />
[http://www.nytimes.com/2009/09/22/technology/internet/22netflix.html A $1 Million Research Bargain for Netflix, and Maybe a Model for Others] Steve Lohr, The New York Times, September 21, 2009.<br />
<br />
[http://bits.blogs.nytimes.com/2009/09/21/netflix-awards-1-million-prize-and-starts-a-new-contest Netflix Awards $1 Million Prize and Starts a New Contest] Steve Lohr, Bits Blog, The New York Times, September 21, 2009.<br />
<br />
Netflix just awarded a million dollar prize in a contest to build a data mining model that could predict what movies its customers would like to see. There was a tight competition between two teams. The winning team, BellKor’s Pragmatic Chaos, was a group of seven "statisticians, machine-learning experts and computer engineers from the United States, Austria, Canada and Israel". The second place team, Ensemble, was "a global alliance with some 30 members."<br />
<br />
<blockquote>The losing team, as it turned out, precisely matched the performance of the winner, but submitted its entry 20 minutes later, just before the final deadline expired. Under contest rules, in the event of a tie, the first team past the post was the winner. “That 20 minutes was worth a million dollars,” Reed Hastings, chief executive of Netflix, said at a news conference in New York.</blockquote><br />
<br />
Netflix has already improved its system to help customers pick movies and thinks the million dollar investment was well spent.<br />
<br />
<blockquote>Thousands of teams from more than 100 nations competed in the Netflix prize contest. And it was a good deal for Netflix. “You look at the cumulative hours and you’re getting Ph.D.’s for a dollar an hour,” Mr. Hastings said in an interview.</blockquote><br />
<br />
The losing team was not too upset.<br />
<br />
<blockquote>Yet the scientists and engineers on the second-place team, and the employers who gave many of them the time and freedom to compete in the contest, were hardly despairing. Arnab Gupta, chief executive of Opera Solutions, a consulting company that specializes in data analytics, based in New York, took a small group of his leading researchers off other work for two years. "We've already had a $10 million payoff internally from what we’ve learned," Mr. Gupta said. Working on the contest helped the researchers come up with improved statistical analysis and predictive modeling techniques that his firm has used with clients in fields like marketing, retailing and finance, he said. "So for us, the $1 million prize was secondary, almost trivial."</blockquote><br />
<br />
The data set itself was the true prize to many team members.<br />
<br />
<blockquote>Win or lose, researchers agreed that they entered the contest in good part to get access to the Netflix data. "It was incredibly alluring to work on such a large, high-quality data set," said Joe Sill, an independent consultant and machine-learning expert who was a member of the Ensemble.</blockquote><br />
<br />
Submitted by Steve Simon<br />
<br />
==Flu Shots==<br />
<br />
The Wall Street Journal of September 24, 2009 reports on a study in the current issue of the New England Journal of Medicine dealing with the efficacy of flu shots during the “2007-2008 flu season.” There were “1952 healthy adults who received either a placebo or one of two [types of] vaccinations,” either a shot or a spray. <br />
<br />
“Of the 813 volunteers who received the flu shot, 28 of them or 3.4%, later developed a confirmed case of influenza. In the FluMist group; 56 of the 814 volunteers, or 6.9% developed the flu, while 10.8% of the placebo group had confirmed flu cases.”<br />
<br />
Discussion<br />
<br />
1. Here is the Minitab output for the comparison between the two forms of vaccination:<br />
<br />
Test and CI for Two Proportions <br />
<br />
<table width="50%" border="1"><br />
<tr><br />
<td>Sample</td><br />
<td>X</td><br />
<td>N</td><br />
<td>Sample p</td><br />
</tr><br />
<tr><br />
<td>1</td><br />
<td>56</td><br />
<td>814</td><br />
<td>0.068796</td><br />
</tr><br />
<tr><br />
<td>2</td><br />
<td>28</td><br />
<td>813</td><br />
<td>0.034440</td><br />
</tr><br />
</table><br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.0343557<br><br />
95% CI for difference: (0.0129208, 0.0557907)<br><br />
Test for difference = 0 (vs not = 0): Z = 3.14 P-Value = 0.002<br />
<br />
Fisher's exact test: P-Value = 0.002<br />
<br />
How does this output support the conclusion that the shot works better than the spray?<br />
<br />
2. Because the number of volunteers is 1952 and the total number in the control arms is 1627 (814 + 813), the number of volunteers who received the placebo is 325. Below it’s the Minitab output comparing the controls vs. the placebo:<br />
<br />
Test and CI for Two Proportions <br />
<br />
<table width="50%" border="1"><br />
<tr><br />
<td>Sample</td><br />
<td>X</td><br />
<td>N</td><br />
<td>Sample p</td><br />
</tr><br />
<tr><br />
<td>1</td><br />
<td>35</td><br />
<td>325</td><br />
<td>0.107692</td><br />
</tr><br />
<tr><br />
<td>2</td><br />
<td>84</td><br />
<td>1627</td><br />
<td>0.051629</td><br />
</tr><br />
</table><br />
<br />
<br />
<br />
Difference = p (1) - p (2)<br><br />
Estimate for difference: 0.0560635<br><br />
95% CI for difference: (0.0206880, 0.0914391<br><br />
Test for difference = 0 (vs not = 0): Z = 3.86 P-Value = 0.000<br />
<br />
Fisher's exact test: P-Value = 0.000<br />
<br />
How does this support the conclusion that the vaccinations work better than the placebo?<br />
<br />
3. According to the article, the makers of the shot, Sanofi Pasteur, “provided funding for the study” and the lead author “reports receiving lecture fees from the company.” No mention is made of MedImmune Inc., makers of the spray. How does this modify your conclusions?<br />
<br />
4. Roughly 5% (84 of 1627) of those who received a vaccination still became confirmed flu victims. Find a friendly librarian to determine how this compares with vaccinations for other diseases such as measles, mumps, rubella, chicken pox and shingles.<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_55&diff=9121Chance News 552009-09-25T20:28:14Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Populism, in its latest manifestation, celebrates ignorant opinion and undifferentiated rage. .... The typical opinion poll … doesn’t trouble to ask whether the respondent knows the first thing about the topic being opined upon, and no conventional poll disqualifies an answer on the ground of mere total ignorance. The premise of opinion polling is that people are, and of right ought to be, omni-opinionated – that they should have views on all subjects at all times – and that all such views are equally valid. …. So, given the prominence of polls in our political culture, it’s no surprise that people have come to believe that their opinions on the issues of the day need not be fettered by either facts or reflection. …. Now there’s the intellectual free lunch: I’m entitled to vociferous opinions on any subject, without having to know, or even think, about it.</blockquote><br />
<br />
<div align=right>Michael Kinsley, <i>The New Yorker</i>, February 6, 1995</div align=right)><br />
<br />
-----<br />
<blockquote>We live in a world of real dangers and imagined fears. …. We are hounded by what I call “psycho-facts”: beliefs that, though not supported by hard evidence, are taken as real because their constant repetition changes the way we experience life. …. We act as if there’s a constitutional right to immortality and that anything that raises risk should be outlawed. <br />
….</blockquote><br />
<div align=right>Robert J. Samuelson, <i>Newsweek</i>, May 9, 1994</div align=right><br />
<br />
-----<br />
In a September 18 <i>Statesman Journal</i> story, [http://www.statesmanjournal.com/article/20090918/SPORTS/909180329/1001/news “Ducks’ defense faces tough challenge”], a coach was quoted:<br />
<blockquote>The only statistic that counts is winning and losing …. We don't get caught up in that. .... How many yards and those things.</blockquote><br />
<br />
-----<br />
A retiring associate professor of math at BVU was described in a <i>Storm Lake Pilot Tribune</i> article [http://www.zwire.com/site/news.cfm?newsid=20370394&BRD=1304&PAG=461&dept_id=180485&rfi=6]<br />
of September 17:<br />
<blockquote>His love for math outweighed his love of sports by a few percentage points.</blockquote><br />
<br />
-----<br />
<blockquote>The plain fact is that 70 years ago Ronald Fisher gave scientists<br />
a mathematical machine for turning baloney into breakthroughs,<br />
and flukes into funding. It is time to pull the plug.</blockquote><br />
<br />
[http://www2.isye.gatech.edu/~brani/isyebayes/bank/pvalue.pdf Robert Mathews] commenting on medical studies which have a low p-value and thus are statistically significant but subsequently turn out to be duds when expanded to the general population.<br />
<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Forsooths==<br />
<br />
Responding to a Canadian viewer who pointed out that "life expectancy in Canada under our health system is higher than the USA," Fox's Bill O'Reilly on 7/27/09 said, <blockquote>Well, that's to be expected, Peter, because we have 10 times as many people as you do. That translates to 10 times as many accidents, crimes, down the line.</blockquote><br />
<br />
-----<br />
According to a September 18 FOX8 News WVUE-TV story, [http://www.fox8live.com/news/local/story/Chance-for-rain-confusing-or-useful-statistic/qz46lnCXU06SQhmu3szNQA.cspx “Chance for rain”], the following information was published in a cover story in an early 2009 bulletin of the American Meteorological Society:<br />
<blockquote> [Researchers at the University of Washington] found people in Seattle didn't have much of a grasp for what the probability forecast [of rain] really means, but found the numbers helpful in planning their day.</blockquote><br />
<br />
-----<br />
Hanna Karp, in [http://online.wsj.com/article/SB10001424052970204518504574417392008401168.html “What’s the Point of Cheerleading?”], <i>The Wall Street Journal</i>, September 17, 2009, states:<br />
<blockquote>Risk-assessment experts say it’s hard to get a handle on the perils of cheerleading.</blockquote><br />
<br />
-----<br />
An advertisement in <i>The Wall Street Journal</i>, of September 22, 2009, contained a chart with an interesting legend. See the chart “Effectiveness of virtual vs. in-person meetings,” in [http://www.tia.org/resources/PDFs/ROI/9-03-09_Oxford_Economics.pdf “The Return on Investment of U.S. Business Travel”], prepared by Oxford Economics USA, September 2009, document page 21/pdf page 20.<br><br />
Students might find it challenging to describe in one sentence what it says. They also might be asked to re-create the chart so that it would convey the message more effectively, that is, pass the interocular trauma test.<br />
<br />
==Breaking News==<br />
<br />
<i>The Wall Street Journal</i> of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.” <br />
<br />
<table width="77%" border="1"><br />
<tr> <br />
<td width="24%" height="39">Sample</td><br />
<td width="22%"><p align="center">Reoperations </p><br />
<p align="center">Needed</p></td><br />
<td width="25%"><div align="center">Sample Size</div></td><br />
<td width="29%"><div align="center">Sample Proportion</div></td><br />
</tr><br />
<tr> <br />
<td height="42">Outside Normal Hours</td><br />
<td> <div align="center">28</div></td><br />
<td> <div align="center">82</div></td><br />
<td> <p align="center">.3415</p><br />
<td> <div align="center"></div></td><br />
</tr><br />
<td>Within Normal Hours</td><br />
<td> <div align="center">12</div></td><br />
<td> <div align="center">70</div></td><br />
<td> <div align="center">.1714</div></td><br />
</tr><br />
</table><br />
<br />
The results are:<br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.170035<br />
95% CI for difference: (0.0346494, 0.305420)<br />
Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018<br />
<br />
Fisher's exact test: P-Value = 0.026<br />
<br />
Discussion<br />
<br />
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?<br />
<br />
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Amazon River at age 1,000,003 years==<br />
[http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/ “Metrics mania: Are Americans too reliant on numbers?”]<br> <br />
by John Yemma, <i>The Christian Science Monitor</i>, September 16, 2009<br><br />
<br />
The author first reminds readers of an old joke:<br />
<blockquote>A guy strikes up a conversation with another guy on a long plane flight to South America. They are over the Amazon.<br><br />
Guy 1: “Did you know that the Amazon is 1,000,003 years old?”<br><br />
Guy 2: “Really? How can you be so precise?”<br><br />
Guy 1: “I was on this same flight three years ago, and a geologist told me the Amazon was a million years old.”</blockquote><br />
He then discusses the difficulty with “metrics-based management” efforts, but concludes, in a hopeful vein, with a formula and some encouragement:<br />
<blockquote>Metrics + Grain of Salt = Somewhat Useful Information.<br><br />
Still, even if we can’t trust data absolutely, we can extract meaning. We may not know how old the Amazon really is, but we know one thing for certain: It is three years older than when Guy 1 first flew over it.</blockquote><br />
<br />
A blogger comments [http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/], <br />
<blockquote>So true. I am an European who has lived in the US for almost 20 years. I am constantly amazed at the ‘number obsession’ that seems to rule all areas of society. It may be because this country is so big, that a common measure can only be found in quantities, not qualities.</blockquote><br />
<br />
==Gompertz Law of human mortality==<br />
[http://freakonomics.blogs.nytimes.com/2009/09/14/youre-likely-to-live/ “You’re Likely to Live!”]<br><br />
by “Freakonomics,” <i>The New York Times</i>, September 14, 2009<br> <br />
This very brief article describes the “Gompertz Law of human mortality,” provides some statistics about the different chances of dying at different ages, and refers readers to three websites:<br><br />
(a) Article with Gompertz Law details and graphs: [http://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/ “Your body wasn’t built to last: a lesson from human mortality rates”], "gravity and levity" blog, July 8, 2009.<br><br />
(b) Applet that gives life expectancy at user-selected age: [http://forio.com/simulate/simulation/mbean/death-probability-calculator/ “Death Probability Calculator”], undated.<br><br />
(c) TED video of songs, the first of which relates to aging: [http://www.ted.com/talks/they_might_be_giants_play_at_8_30_am.html “Time is marching on”], March 2007.<br><br />
<br />
==Things that go bump==<br />
[http://online.wsj.com/article/SB10001424052970203278404574416813210135226.html “Bumped Passengers Learn a Cruel Flying Lesson”]<br><br />
by Scott McCartney, <i>The Wall Street Journal</i>, September 17, 2009<br><br />
<br />
This article discusses the recent spike in the rates of passenger-bumping by airlines, despite the increased penalties that the federal government requires the airlines to pay bumped-but-ticketed passengers. Although bumping affects fewer than 2 passengers out of every 10,000, that rate rose by 40% in the second quarter of 2009 over the rate for the second quarter of 2008.<br><br />
<blockquote>It's pretty simple: It's just because planes are more full than last year," says [a US Airways official, whose airline] had the highest bumping rate among major airlines, at 1.88 passengers per 10,000 in the second quarter.<br><br />
This summer, the nine major airlines filled 85.5% of their seats, up from 84.1% last summer. The peak was July, with 86.7% of seats filled.</blockquote> <br />
Federal rules allow airlines to overbook in order to compensate for no-shows. The recent increase in bumping rates may be explained by the reduced demand for air travel, especially by business customers.<br />
<blockquote>The [Department of Transportation] says it isn't concerned about the rise in bumping because the rates are still lower than historical highs. During the 1970s and 1980s, bumping rates were routinely four times as high as today's rate.</blockquote><br />
<br />
<b>Discussion</b><br><br />
<br />
Suppose that, on average, 85% of ticket-holders show up for their flights. Assume that the distribution of the number of ticket-holders who show up is binomial (especially that every ticket-holder has the same chance of being bumped) and that a ticket-holder is bumped only due to lack of a seat.<br><br />
<br />
1. For each n tickets sold, or over-sold, for a 200-seat plane, find the number of ticket-holders an airline could expect to show up, on average.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
2. It appears that the airline would not have to bump any ticket-holders for some values of n. Is that a statistically correct inference, based on your understanding of expected value? Even if those expected values always “came true,” what problem would remain for the airline?<br> <br />
<br />
3. For each n tickets sold, or over-sold, find the probability of at least one ticket-holder being bumped off the 200-seat plane.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
4. For which value(s) of n would you have a negligible risk of being bumped? Under what circumstances might any risk be too great?<br><br />
<br />
5. The more tickets an airline sells, the more likely it is to fill the plane and thus maximize its revenue for a flight. However, at some point, the increased revenue may be offset by losses of future dollars from angry ticket-holders and compensation payouts to increasing numbers of bumped ticket-holders. What other information would you want/need to know before deciding how many tickets to sell for a 200-seat plane?<br><br />
<br />
6. Do you agree with the "pretty simple" reason given for the increased rate of bumping?<br />
<br />
==The Bulgarian Toto 6 of 42 lottery== <br />
<br />
The Bulgarian Toto 6 of 42 lottery was the subject of an investigation after the <br />
same set of six numbers {4, 15, 23, 24, 35, 42} was drawn in two successive lotteries on September 6 and September 10, 2009. The article [http://www.novinite.com/view_news.php?id=107914] cites a mathematician as stating that the probability of picking the same six numbers twice in a row is 4,200,000:1. We wondered how he arrived at this number. What is the probability that a specified set of six numbers will repeat consecutively?<br />
<br />
There are <math>{42 \choose 6} = 5245786</math> different sets of six numbers and the probability that a SPECIFIED set will occur in the next two consecutive draws is <math>1/5245786^2</math>. Because the sets involve disjoint events, the probability that SOME set will occur in the next two consecutive draws is <math>5245786 \times 1/5245786^2 = 1/5245786</math>. <br />
<br />
But now, suppose the lottery has been running continuously for <math>m</math> draws and we ask what the chance is that during this period there were consecutive draws of the same set. As before, first consider a fixed set of six numbers.<br />
<br />
There are <math>m-1</math> opportunities for this set to be drawn twice in succession (beginning with the second drawing). The probability that this will happen is then the probability of the union <math>P(A) = P(\cup_i A_i A_{i+1}) </math> where <math>A_i</math> is the event that this set of numbers is drawn on the ith draw.<br />
<br />
Bonferroni's first degree upper bound is <math>P(A) \le \sum_i P(A_i A_{i+1})</math> while the second degree lower bound is<br />
<math>P(A) \ge \sum_i P(A_i A_{i+1}) - \sum_{1 \le i < j \le m}P(A_i A_{i+1} A_j A_{j+1}).</math><br />
<br />
We assume (!) that the events <math>A_i</math> are independent and identically distributed with probability <math>p = 1/5245786</math>. As long as <br />
<math>mp</math> is small the second sum in the lower bound can be ignored, giving <math>P(A) \approx (m-1)/5245786^2.</math><br />
<br />
It appears that the draws are held twice per week so for one year <math>m = 104</math> giving the probability <math>3.74 \times 10^{-12}</math> that a specified set of numbers will be drawn twice in succession. According to a spokeswoman the lottery has been taking place for 52 years<br />
[http://www.canada.com/Bulgaria+identical+lottery+draw+just+coincidence/2003980/story.html?id=2003980x]. <br />
Using <math>m = 104 \times 52 = 5408</math>, the probability that a specified set of numbers will be drawn twice in succession over this period is <math>1.89 \times 10^{-10}</math>, still very small.<br />
<br />
But now let's ask the question, not for a fixed set of numbers but for some set of numbers. After all, in discussing this coincidence the repeated set arises by chance alone and is not specified in advance.<br />
<br />
In <math>m</math> drawings what is the probability that SOME set of six numbers will be repeated in consecutive draws.<br />
<br />
There are 5245786 possible sets of numbers that could be repeated. Enumerate the sets by integers <br />
<math>1 \le k ≤ \le 5245786</math> with <math>E_k</math> the event that set <math>k</math> repeats consecutively sometime during <br />
these <math>m</math> drawings. The probability of the union <math>P(\cup E_k)</math> is needed. Each of the 5245786 events <br />
<math>E_k</math> has probability <math>(m-1)/ 5245786^2</math> and if they were independent we could evaluate the probability using complements as <br />
<math>P(\cup E_k) = 1 - (1- (m-1)/5245786^2)^{5245786} \approx 1 - e^{-(m-1)/5245786}</math>. However, they are dependent, but as long as <math>mp</math> is small Bonferroni's bounds can once again be used to estimate <br />
<math>P(\cup E_k) \approx (m-1)/5245786.</math> For <math>m = 5408</math> this is 0.0010302. (Note that assuming independence gives 0.0010307.)<br />
<br />
This probability relates to one lottery. Suppose we consider all lotteries worldwise and ask for the probability that in some lottery, somewhere, some set of numbers will be repeated consecutively. All lotteries are variants of Toto with different numbers involved. Each lottery will have had its own cumulative number of drawings. In order to gauge the magnitude of the probability wanted, assume that there are <math>x</math> lotteries, each one sharing the same numerical characteristics as the Bulgarian one.<br />
<br />
This time we can use independence. The probability that some set will be repeated is 1 minus the probability that in no lottery is a set of numbers selected on two consecutive drawings <br />
<math>= 1 - (1 - (m -1)/5245786)^x</math>. For <math>x = 50</math> this is 0.0503 while for <math>x = 100</math> the probability is 0.0980. (An approximation to one significant digit for this range of values of interest is <math>x(m-1)/5245786.</math>)<br />
<br />
For a different problem that discusses "very big numbers" see the article about double lottery winners [http://www.nytimes.com/1990/02/27/science/1-in-a-trillion-coincidence-you-say-not-really-experts-find.html?pagewanted=all].<br />
<br />
Questions.<br />
<br />
1. Can you verify both assertions concerning the Bonferroni lower bound.<br />
<br />
2. How many years would the Bulgarian lottery need to be running in order to have the same probability that some set of numbers will appear three times in succession?<br />
<br />
3. Instead of demanding that the same set of numbers appear twice in succession, what is the probability that some set of numbers will repeat during <math>m</math> drawings? (This is simpler and is the famous birthday problem)<br />
<br />
Submitted by Fred Hoppe<br />
<br />
==Baby, it’s cold outside==<br />
[http://online.wsj.com/article/SB125356566517528879.html “New Light on the Plight of Winter Babies”]<br><br />
by Justin Lahart, <i>The Wall Street Journal</i>, September 22, 2009<br><br />
<br />
Two Notre Dame economists “may have uncovered an overlooked explanation for why season of birth matters” with respect to the often reported poor test results, less healthiness, reduced longevity, and lower school completion rates and earnings of children born in the winter. See [http://www.nd.edu/~dhungerm/w14573.pdf “Season of Birth and Later Outcomes: Old Questions, New Answers”], by Kasey Buckles and Daniel Hungerman, National Bureau of Economic Research, December 2008.<br><br />
<br />
Working independently, Hungerman found that “children in the same families tend to be born at the same time of year,” and Buckles found a “tendency that less educated mothers were having children in winter.” They put their heads together and concluded that:<br />
<br />
<blockquote>A key assumption of much of [the previous] research is that the backgrounds of children born in the winter are the same as the backgrounds of children born at other times of the year.</blockquote><br />
<br />
Some previous explanations for seasonal birth differences were school attendance laws, the amount of sunshine available in a season, or the level of pesticides in the water in a season. With respect to the first explanation, economists Joshua Angrist of MIT and Alan Krueger of Princeton posited in 1991 that, since winter babies can drop out of school earlier because they reach their 16th birthdays earlier, those babies have lower education levels that, in turn, lead to lower earnings.<br><br />
<br />
Upon examination of CDC birth-certificate data for virtually all 52 million children born during the period 1989-2001, the Notre Dame researchers noted:<br />
<br />
<blockquote>The percentage of children born to unwed mothers, teenage mothers and mothers who hadn't completed high school kept peaking in January every year. Over the 13-year period, for example, 13.2% of January births were to teen mothers, compared with 12% in May -- a small but statistically significant difference, they say.</blockquote><br />
<br />
A Columbia University economist comments about how striking the Notre Dame results are: "You can take a look at those graphs and see the clear pattern and that it's remarkably stable over time." See graphs [http://online.wsj.com/article/SB125356566517528879.html] of January and May births with respect to birth mother’s marital status, age, and education.<br><br />
<br />
Angrist disagrees, stating "The bottom line is a slight change in the estimate. …. It hardly overturns our finding."<br><br />
<br />
Buckles and Hungerman are now working on finding an explanation of why a mother’s socioeconomic status is related to a child’s birth month.<br> <br />
<br />
(As of September 24, there were 298 blogs [http://online.wsj.com/article/SB125356566517528879.html#articleTabs%3Dcomments] responding to this article!)<br />
<br />
==U.S. Census: 2008 sampling results released==<br />
The U.S. Census Bureau has released the 2008 results of its ongoing [http://www.census.gov/acs/www/ "American Community Survey"].<br />
<br />
==Tennis challenges are underused==<br />
<br />
[http://www.nytimes.com/2009/09/21/opinion/21kedrosky.html Challenge, Anyone?] Paul Kedrosky, The New York Times, September 20, 2009<br />
<br />
It seems like economists have an opinion about just about everything. Paul Kedrosky, described in the New York Times as "senior fellow at the Kauffman Foundation, a center for economic research," has advice for professional tennis players. Challenge the line judges more often.<br />
<br />
Like in American football, tennis players can challenge a judges ruling.<br />
<br />
<blockquote>Here’s how challenges work. Major tennis tournaments (like the U.S. Open) have multiple cameras arrayed around the court. This permits a simulated replay of a shot, showing to the millimeter where a ball landed on the court. So instead of futilely shouting, "You can't be serious!" at linesmen and umpires, players can raise their hand immediately after a call and ask for a replay.</blockquote><br />
<br />
There are limits to how often you can challenge.<br />
<br />
<blockquote>The rules allow three incorrect challenges per player per set. In a best-of-five-sets match (which is normal for men), that means at least 18 available challenges per match, none of which carry over from set to set.In other words, use ’em or lose ’em. A player can get an additional challenge if the match goes into a tiebreaker, or if a fifth set goes overtime.</blockquote><br />
<br />
But most tennis players don't come even close to using all of their available challenges. And they should according to Kedrosky. Here's one scenario he proposes:<br />
<br />
<blockquote>For example, the No. 10 seed at the Open, Fernando Verdasco of Spain, averaged 0.4 challenges per set and had a sparkling 43 percent success rate. If he challenged once per set, like Federer, and his challenge success rate fell to a similar 30 percent, it could mean one more point to him in a three-set match. If his success rate didn’t fall as much, however, and he challenged twice per set it might mean as many as three more points in a five-set match. Either way, it could be the difference between winning and losing.</blockquote><br />
<br />
There are other factors at work, such as embarrassment when a challenge does not go your way, but Kedrosky thinks players should ignore this.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Suppose you wanted to run a computer simulation about close calls in tennis and vary the rate at which players challenge close calls. What are some of the rnadom variables that you would have to account for in such a simulation?<br />
<br />
2. How much of an edge would one more point mean in a match between two players who are otherwise evenly matched?<br />
<br />
==Netflix data mining contest==<br />
<br />
[http://www.nytimes.com/2009/09/22/technology/internet/22netflix.html A $1 Million Research Bargain for Netflix, and Maybe a Model for Others] Steve Lohr, The New York Times, September 21, 2009.<br />
<br />
[http://bits.blogs.nytimes.com/2009/09/21/netflix-awards-1-million-prize-and-starts-a-new-contest Netflix Awards $1 Million Prize and Starts a New Contest] Steve Lohr, The New York Times, September 21, 2009.<br />
<br />
Netflix just awarded a million dollar prize in a contest to build a data mining model that could predict what movies its customers would like to see.</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_55&diff=9119Chance News 552009-09-25T20:22:14Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Populism, in its latest manifestation, celebrates ignorant opinion and undifferentiated rage. .... The typical opinion poll … doesn’t trouble to ask whether the respondent knows the first thing about the topic being opined upon, and no conventional poll disqualifies an answer on the ground of mere total ignorance. The premise of opinion polling is that people are, and of right ought to be, omni-opinionated – that they should have views on all subjects at all times – and that all such views are equally valid. …. So, given the prominence of polls in our political culture, it’s no surprise that people have come to believe that their opinions on the issues of the day need not be fettered by either facts or reflection. …. Now there’s the intellectual free lunch: I’m entitled to vociferous opinions on any subject, without having to know, or even think, about it.</blockquote><br />
<br />
<div align=right>Michael Kinsley, <i>The New Yorker</i>, February 6, 1995</div align=right)><br />
<br />
-----<br />
<blockquote>We live in a world of real dangers and imagined fears. …. We are hounded by what I call “psycho-facts”: beliefs that, though not supported by hard evidence, are taken as real because their constant repetition changes the way we experience life. …. We act as if there’s a constitutional right to immortality and that anything that raises risk should be outlawed. <br />
….</blockquote><br />
<div align=right>Robert J. Samuelson, <i>Newsweek</i>, May 9, 1994</div align=right><br />
<br />
-----<br />
In a September 18 <i>Statesman Journal</i> story, [http://www.statesmanjournal.com/article/20090918/SPORTS/909180329/1001/news “Ducks’ defense faces tough challenge”], a coach was quoted:<br />
<blockquote>The only statistic that counts is winning and losing …. We don't get caught up in that. .... How many yards and those things.</blockquote><br />
<br />
-----<br />
A retiring associate professor of math at BVU was described in a <i>Storm Lake Pilot Tribune</i> article [http://www.zwire.com/site/news.cfm?newsid=20370394&BRD=1304&PAG=461&dept_id=180485&rfi=6]<br />
of September 17:<br />
<blockquote>His love for math outweighed his love of sports by a few percentage points.</blockquote><br />
<br />
-----<br />
<blockquote>The plain fact is that 70 years ago Ronald Fisher gave scientists<br />
a mathematical machine for turning baloney into breakthroughs,<br />
and flukes into funding. It is time to pull the plug.</blockquote><br />
<br />
<div align=right> [http://www2.isye.gatech.edu/~brani/isyebayes/bank/pvalue.pdf Robert Mathews] commenting on medical studies which have a low p-value and thus are statistically significant but subsequently turn out to be duds when expanded to the general population.<br />
</div align=right><br />
<br />
Submitted by Paul Alper.<br />
<br />
==Forsooths==<br />
<br />
Responding to a Canadian viewer who pointed out that "life expectancy in Canada under our health system is higher than the USA," Fox's Bill O'Reilly on 7/27/09 said, <blockquote>Well, that's to be expected, Peter, because we have 10 times as many people as you do. That translates to 10 times as many accidents, crimes, down the line.</blockquote><br />
<br />
-----<br />
According to a September 18 FOX8 News WVUE-TV story, [http://www.fox8live.com/news/local/story/Chance-for-rain-confusing-or-useful-statistic/qz46lnCXU06SQhmu3szNQA.cspx “Chance for rain”], the following information was published in a cover story in an early 2009 bulletin of the American Meteorological Society:<br />
<blockquote> [Researchers at the University of Washington] found people in Seattle didn't have much of a grasp for what the probability forecast [of rain] really means, but found the numbers helpful in planning their day.</blockquote><br />
<br />
-----<br />
Hanna Karp, in [http://online.wsj.com/article/SB10001424052970204518504574417392008401168.html “What’s the Point of Cheerleading?”], <i>The Wall Street Journal</i>, September 17, 2009, states:<br />
<blockquote>Risk-assessment experts say it’s hard to get a handle on the perils of cheerleading.</blockquote><br />
<br />
-----<br />
An advertisement in <i>The Wall Street Journal</i>, of September 22, 2009, contained a chart with an interesting legend. See the chart “Effectiveness of virtual vs. in-person meetings,” in [http://www.tia.org/resources/PDFs/ROI/9-03-09_Oxford_Economics.pdf “The Return on Investment of U.S. Business Travel”], prepared by Oxford Economics USA, September 2009, document page 21/pdf page 20.<br><br />
Students might find it challenging to describe in one sentence what it says. They also might be asked to re-create the chart so that it would convey the message more effectively, that is, pass the interocular trauma test.<br />
<br />
==Breaking News==<br />
<br />
<i>The Wall Street Journal</i> of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.” <br />
<br />
<table width="77%" border="1"><br />
<tr> <br />
<td width="24%" height="39">Sample</td><br />
<td width="22%"><p align="center">Reoperations </p><br />
<p align="center">Needed</p></td><br />
<td width="25%"><div align="center">Sample Size</div></td><br />
<td width="29%"><div align="center">Sample Proportion</div></td><br />
</tr><br />
<tr> <br />
<td height="42">Outside Normal Hours</td><br />
<td> <div align="center">28</div></td><br />
<td> <div align="center">82</div></td><br />
<td> <p align="center">.3415</p><br />
<td> <div align="center"></div></td><br />
</tr><br />
<td>Within Normal Hours</td><br />
<td> <div align="center">12</div></td><br />
<td> <div align="center">70</div></td><br />
<td> <div align="center">.1714</div></td><br />
</tr><br />
</table><br />
<br />
The results are:<br />
<br />
Difference = p (1) - p (2)<br />
Estimate for difference: 0.170035<br />
95% CI for difference: (0.0346494, 0.305420)<br />
Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018<br />
<br />
Fisher's exact test: P-Value = 0.026<br />
<br />
Discussion<br />
<br />
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?<br />
<br />
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.<br />
<br />
Submitted by Paul Alper.<br />
<br />
==Amazon River at age 1,000,003 years==<br />
[http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/ “Metrics mania: Are Americans too reliant on numbers?”]<br> <br />
by John Yemma, <i>The Christian Science Monitor</i>, September 16, 2009<br><br />
<br />
The author first reminds readers of an old joke:<br />
<blockquote>A guy strikes up a conversation with another guy on a long plane flight to South America. They are over the Amazon.<br><br />
Guy 1: “Did you know that the Amazon is 1,000,003 years old?”<br><br />
Guy 2: “Really? How can you be so precise?”<br><br />
Guy 1: “I was on this same flight three years ago, and a geologist told me the Amazon was a million years old.”</blockquote><br />
He then discusses the difficulty with “metrics-based management” efforts, but concludes, in a hopeful vein, with a formula and some encouragement:<br />
<blockquote>Metrics + Grain of Salt = Somewhat Useful Information.<br><br />
Still, even if we can’t trust data absolutely, we can extract meaning. We may not know how old the Amazon really is, but we know one thing for certain: It is three years older than when Guy 1 first flew over it.</blockquote><br />
<br />
A blogger comments [http://features.csmonitor.com/connectingthedots/2009/09/16/metrics-mania-are-americans-too-reliant-on-numbers/], <br />
<blockquote>So true. I am an European who has lived in the US for almost 20 years. I am constantly amazed at the ‘number obsession’ that seems to rule all areas of society. It may be because this country is so big, that a common measure can only be found in quantities, not qualities.</blockquote><br />
<br />
==Gompertz Law of human mortality==<br />
[http://freakonomics.blogs.nytimes.com/2009/09/14/youre-likely-to-live/ “You’re Likely to Live!”]<br><br />
by “Freakonomics,” <i>The New York Times</i>, September 14, 2009<br> <br />
This very brief article describes the “Gompertz Law of human mortality,” provides some statistics about the different chances of dying at different ages, and refers readers to three websites:<br><br />
(a) Article with Gompertz Law details and graphs: [http://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/ “Your body wasn’t built to last: a lesson from human mortality rates”], "gravity and levity" blog, July 8, 2009.<br><br />
(b) Applet that gives life expectancy at user-selected age: [http://forio.com/simulate/simulation/mbean/death-probability-calculator/ “Death Probability Calculator”], undated.<br><br />
(c) TED video of songs, the first of which relates to aging: [http://www.ted.com/talks/they_might_be_giants_play_at_8_30_am.html “Time is marching on”], March 2007.<br><br />
<br />
==Things that go bump==<br />
[http://online.wsj.com/article/SB10001424052970203278404574416813210135226.html “Bumped Passengers Learn a Cruel Flying Lesson”]<br><br />
by Scott McCartney, <i>The Wall Street Journal</i>, September 17, 2009<br><br />
<br />
This article discusses the recent spike in the rates of passenger-bumping by airlines, despite the increased penalties that the federal government requires the airlines to pay bumped-but-ticketed passengers. Although bumping affects fewer than 2 passengers out of every 10,000, that rate rose by 40% in the second quarter of 2009 over the rate for the second quarter of 2008.<br><br />
<blockquote>It's pretty simple: It's just because planes are more full than last year," says [a US Airways official, whose airline] had the highest bumping rate among major airlines, at 1.88 passengers per 10,000 in the second quarter.<br><br />
This summer, the nine major airlines filled 85.5% of their seats, up from 84.1% last summer. The peak was July, with 86.7% of seats filled.</blockquote> <br />
Federal rules allow airlines to overbook in order to compensate for no-shows. The recent increase in bumping rates may be explained by the reduced demand for air travel, especially by business customers.<br />
<blockquote>The [Department of Transportation] says it isn't concerned about the rise in bumping because the rates are still lower than historical highs. During the 1970s and 1980s, bumping rates were routinely four times as high as today's rate.</blockquote><br />
<br />
<b>Discussion</b><br><br />
<br />
Suppose that, on average, 85% of ticket-holders show up for their flights. Assume that the distribution of the number of ticket-holders who show up is binomial (especially that every ticket-holder has the same chance of being bumped) and that a ticket-holder is bumped only due to lack of a seat.<br><br />
<br />
1. For each n tickets sold, or over-sold, for a 200-seat plane, find the number of ticket-holders an airline could expect to show up, on average.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
2. It appears that the airline would not have to bump any ticket-holders for some values of n. Is that a statistically correct inference, based on your understanding of expected value? Even if those expected values always “came true,” what problem would remain for the airline?<br> <br />
<br />
3. For each n tickets sold, or over-sold, find the probability of at least one ticket-holder being bumped off the 200-seat plane.<br><br />
(a) n = 200 (b) n = 210 (c) n = 220 (d) n = 230 (e) n = 240 (f) n = 250.<br><br />
<br />
4. For which value(s) of n would you have a negligible risk of being bumped? Under what circumstances might any risk be too great?<br><br />
<br />
5. The more tickets an airline sells, the more likely it is to fill the plane and thus maximize its revenue for a flight. However, at some point, the increased revenue may be offset by losses of future dollars from angry ticket-holders and compensation payouts to increasing numbers of bumped ticket-holders. What other information would you want/need to know before deciding how many tickets to sell for a 200-seat plane?<br><br />
<br />
6. Do you agree with the "pretty simple" reason given for the increased rate of bumping?<br />
<br />
==The Bulgarian Toto 6 of 42 lottery== <br />
<br />
The Bulgarian Toto 6 of 42 lottery was the subject of an investigation after the <br />
same set of six numbers {4, 15, 23, 24, 35, 42} was drawn in two successive lotteries on September 6 and September 10, 2009. The article [http://www.novinite.com/view_news.php?id=107914] cites a mathematician as stating that the probability of picking the same six numbers twice in a row is 4,200,000:1. We wondered how he arrived at this number. What is the probability that a specified set of six numbers will repeat consecutively?<br />
<br />
There are <math>{42 \choose 6} = 5245786</math> different sets of six numbers and the probability that a SPECIFIED set will occur in the next two consecutive draws is <math>1/5245786^2</math>. Because the sets involve disjoint events, the probability that SOME set will occur in the next two consecutive draws is <math>5245786 \times 1/5245786^2 = 1/5245786</math>. <br />
<br />
But now, suppose the lottery has been running continuously for <math>m</math> draws and we ask what the chance is that during this period there were consecutive draws of the same set. As before, first consider a fixed set of six numbers.<br />
<br />
There are <math>m-1</math> opportunities for this set to be drawn twice in succession (beginning with the second drawing). The probability that this will happen is then the probability of the union <math>P(A) = P(\cup_i A_i A_{i+1}) </math> where <math>A_i</math> is the event that this set of numbers is drawn on the ith draw.<br />
<br />
Bonferroni's first degree upper bound is <math>P(A) \le \sum_i P(A_i A_{i+1})</math> while the second degree lower bound is<br />
<math>P(A) \ge \sum_i P(A_i A_{i+1}) - \sum_{1 \le i < j \le m}P(A_i A_{i+1} A_j A_{j+1}).</math><br />
<br />
We assume (!) that the events <math>A_i</math> are independent and identically distributed with probability <math>p = 1/5245786</math>. As long as <br />
<math>mp</math> is small the second sum in the lower bound can be ignored, giving <math>P(A) \approx (m-1)/5245786^2.</math><br />
<br />
It appears that the draws are held twice per week so for one year <math>m = 104</math> giving the probability <math>3.74 \times 10^{-12}</math> that a specified set of numbers will be drawn twice in succession. According to a spokeswoman the lottery has been taking place for 52 years<br />
[http://www.canada.com/Bulgaria+identical+lottery+draw+just+coincidence/2003980/story.html?id=2003980x]. <br />
Using <math>m = 104 \times 52 = 5408</math>, the probability that a specified set of numbers will be drawn twice in succession over this period is <math>1.89 \times 10^{-10}</math>, still very small.<br />
<br />
But now let's ask the question, not for a fixed set of numbers but for some set of numbers. After all, in discussing this coincidence the repeated set arises by chance alone and is not specified in advance.<br />
<br />
In <math>m</math> drawings what is the probability that SOME set of six numbers will be repeated in consecutive draws.<br />
<br />
There are 5245786 possible sets of numbers that could be repeated. Enumerate the sets by integers <br />
<math>1 \le k ≤ \le 5245786</math> with <math>E_k</math> the event that set <math>k</math> repeats consecutively sometime during <br />
these <math>m</math> drawings. The probability of the union <math>P(\cup E_k)</math> is needed. Each of the 5245786 events <br />
<math>E_k</math> has probability <math>(m-1)/ 5245786^2</math> and if they were independent we could evaluate the probability using complements as <br />
<math>P(\cup E_k) = 1 - (1- (m-1)/5245786^2)^{5245786} \approx 1 - e^{-(m-1)/5245786}</math>. However, they are dependent, but as long as <math>mp</math> is small Bonferroni's bounds can once again be used to estimate <br />
<math>P(\cup E_k) \approx (m-1)/5245786.</math> For <math>m = 5408</math> this is 0.0010302. (Note that assuming independence gives 0.0010307.)<br />
<br />
This probability relates to one lottery. Suppose we consider all lotteries worldwise and ask for the probability that in some lottery, somewhere, some set of numbers will be repeated consecutively. All lotteries are variants of Toto with different numbers involved. Each lottery will have had its own cumulative number of drawings. In order to gauge the magnitude of the probability wanted, assume that there are <math>x</math> lotteries, each one sharing the same numerical characteristics as the Bulgarian one.<br />
<br />
This time we can use independence. The probability that some set will be repeated is 1 minus the probability that in no lottery is a set of numbers selected on two consecutive drawings <br />
<math>= 1 - (1 - (m -1)/5245786)^x</math>. For <math>x = 50</math> this is 0.0503 while for <math>x = 100</math> the probability is 0.0980. (An approximation to one significant digit for this range of values of interest is <math>x(m-1)/5245786.</math>)<br />
<br />
For a different problem that discusses "very big numbers" see the article about double lottery winners [http://www.nytimes.com/1990/02/27/science/1-in-a-trillion-coincidence-you-say-not-really-experts-find.html?pagewanted=all].<br />
<br />
Questions.<br />
<br />
1. Can you verify both assertions concerning the Bonferroni lower bound.<br />
<br />
2. How many years would the Bulgarian lottery need to be running in order to have the same probability that some set of numbers will appear three times in succession?<br />
<br />
3. Instead of demanding that the same set of numbers appear twice in succession, what is the probability that some set of numbers will repeat during <math>m</math> drawings? (This is simpler and is the famous birthday problem)<br />
<br />
Submitted by Fred Hoppe<br />
<br />
==Baby, it’s cold outside==<br />
[http://online.wsj.com/article/SB125356566517528879.html “New Light on the Plight of Winter Babies”]<br><br />
by Justin Lahart, <i>The Wall Street Journal</i>, September 22, 2009<br><br />
<br />
Two Notre Dame economists “may have uncovered an overlooked explanation for why season of birth matters” with respect to the often reported poor test results, less healthiness, reduced longevity, and lower school completion rates and earnings of children born in the winter. See [http://www.nd.edu/~dhungerm/w14573.pdf “Season of Birth and Later Outcomes: Old Questions, New Answers”], by Kasey Buckles and Daniel Hungerman, National Bureau of Economic Research, December 2008.<br><br />
<br />
Working independently, Hungerman found that “children in the same families tend to be born at the same time of year,” and Buckles found a “tendency that less educated mothers were having children in winter.” They put their heads together and concluded that:<br />
<br />
<blockquote>A key assumption of much of [the previous] research is that the backgrounds of children born in the winter are the same as the backgrounds of children born at other times of the year.</blockquote><br />
<br />
Some previous explanations for seasonal birth differences were school attendance laws, the amount of sunshine available in a season, or the level of pesticides in the water in a season. With respect to the first explanation, economists Joshua Angrist of MIT and Alan Krueger of Princeton posited in 1991 that, since winter babies can drop out of school earlier because they reach their 16th birthdays earlier, those babies have lower education levels that, in turn, lead to lower earnings.<br><br />
<br />
Upon examination of CDC birth-certificate data for virtually all 52 million children born during the period 1989-2001, the Notre Dame researchers noted:<br />
<br />
<blockquote>The percentage of children born to unwed mothers, teenage mothers and mothers who hadn't completed high school kept peaking in January every year. Over the 13-year period, for example, 13.2% of January births were to teen mothers, compared with 12% in May -- a small but statistically significant difference, they say.</blockquote><br />
<br />
A Columbia University economist comments about how striking the Notre Dame results are: "You can take a look at those graphs and see the clear pattern and that it's remarkably stable over time." See graphs [http://online.wsj.com/article/SB125356566517528879.html] of January and May births with respect to birth mother’s marital status, age, and education.<br><br />
<br />
Angrist disagrees, stating "The bottom line is a slight change in the estimate. …. It hardly overturns our finding."<br><br />
<br />
Buckles and Hungerman are now working on finding an explanation of why a mother’s socioeconomic status is related to a child’s birth month.<br> <br />
<br />
(As of September 24, there were 298 blogs [http://online.wsj.com/article/SB125356566517528879.html#articleTabs%3Dcomments] responding to this article!)<br />
<br />
==U.S. Census: 2008 sampling results released==<br />
The U.S. Census Bureau has released the 2008 results of its ongoing [http://www.census.gov/acs/www/ "American Community Survey"].<br />
<br />
==Tennis challenges are underused==<br />
<br />
[http://www.nytimes.com/2009/09/21/opinion/21kedrosky.html Challenge, Anyone?] Paul Kedrosky, The New York Times, September 20, 2009<br />
<br />
It seems like economists have an opinion about just about everything. Paul Kedrosky, described in the New York Times as "senior fellow at the Kauffman Foundation, a center for economic research," has advice for professional tennis players. Challenge the line judges more often.<br />
<br />
Like in American football, tennis players can challenge a judges ruling.<br />
<br />
<blockquote>Here’s how challenges work. Major tennis tournaments (like the U.S. Open) have multiple cameras arrayed around the court. This permits a simulated replay of a shot, showing to the millimeter where a ball landed on the court. So instead of futilely shouting, "You can't be serious!" at linesmen and umpires, players can raise their hand immediately after a call and ask for a replay.</blockquote><br />
<br />
There are limits to how often you can challenge.<br />
<br />
<blockquote>The rules allow three incorrect challenges per player per set. In a best-of-five-sets match (which is normal for men), that means at least 18 available challenges per match, none of which carry over from set to set.In other words, use ’em or lose ’em. A player can get an additional challenge if the match goes into a tiebreaker, or if a fifth set goes overtime.</blockquote><br />
<br />
But most tennis players don't come even close to using all of their available challenges. And they should according to Kedrosky. Here's one scenario he proposes:<br />
<br />
<blockquote>For example, the No. 10 seed at the Open, Fernando Verdasco of Spain, averaged 0.4 challenges per set and had a sparkling 43 percent success rate. If he challenged once per set, like Federer, and his challenge success rate fell to a similar 30 percent, it could mean one more point to him in a three-set match. If his success rate didn’t fall as much, however, and he challenged twice per set it might mean as many as three more points in a five-set match. Either way, it could be the difference between winning and losing.</blockquote><br />
<br />
There are other factors at work, such as embarrassment when a challenge does not go your way, but Kedrosky thinks players should ignore this.<br />
<br />
Submitted by Steve Simon<br />
<br />
===Questions===<br />
<br />
1. Suppose you wanted to run a computer simulation about close calls in tennis and vary the rate at which players challenge close calls. What are some of the rnadom variables that you would have to account for in such a simulation?<br />
<br />
2. How much of an edge would one more point mean in a match between two players who are otherwise evenly matched?<br />
<br />
==Netflix data mining contest==<br />
<br />
[http://www.nytimes.com/2009/09/22/technology/internet/22netflix.html A $1 Million Research Bargain for Netflix, and Maybe a Model for Others] Steve Lohr, The New York Times, September 21, 2009</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8646Chance News 532009-08-18T16:19:22Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
From [http://www.imbs.uci.edu/Stern.pdf Bayesian statistics for experimental scientists] written by Hal Stern, Department of Statistics, University of California, Irvine:<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (<i>Biometrical Interpretation</i>, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
Submitted by Paul Alper<br />
<br />
<blockquote>Bueno de Mesquita does not express his forecasts in probabilistic terms; <br><br />
he says an event will transpire or it won't.</blockquote><br />
<br />
<div align=right>Clive Thompson <br><br />
[http://www.nytimes.com/glogin?URI=http://www.nytimes.com/2009/08/16/magazine/16Bruce-t.html&OQ=_rQ3D1Q26hpw&OP=df3ed54Q2FyvBQ3CyQ5CmQ5BYNmmkQ2ByQ2BKK2yKQ20yEJyTQ27cQ27uFQ5DByEJQ2AN!Q5BBSkQ60DkTw New York Times] <br><br />
August 16, 2009<br />
<br />
==Fraud Doesn't Always Happen to Someone Else==<br />
<br />
From a <i>Wall Street Journal</i> article [http://online.wsj.com/article/SB10001424052970203674704574334752489414792.html] describing the results of a number of research studies about victims of investment fraud:<br />
<blockquote>The typical investment-scam victim is an optimistic married man in his later 50s who has a higher-than-average knowledge of financial matters and deep confidence in his own judgment …. </blockquote><br />
<blockquote> [A man told] an FTC fraud forum that he preferred speaking with a man because "you can lather him up and push all the green buttons." Women were more cautious and asked too many questions, he said, prompting an office maxim, "Don't pitch to the b—."</blockquote><br><br />
-----<br />
<blockquote> NYT headline: "For Todays Graduate, Just One Word: Statistics" </blockquote> <br />
<div align=right> <i>New York Times</i><BR><br />
Steve Lohr<BR><br />
August 5, 2009</div align=right><br />
You can read the article [http://www.nytimes.com/2009/08/06/technology/06stats.html?hp Here].<br />
<br />
The article is about the Joint Statistical Meetings in Washington this week and how the job market for statisticians is booming. This is said to be a product of the recent explosion of digital data. Here is the accompanying picture:<br />
<br />
http://graphics8.nytimes.com/images/2009/08/06/business/stats2_190.jpg<br><br />
<br />
-----<br />
<br />
<blockquote>Odds determine our interest in otherwise mundane action.</blockquote><br />
<div align=right>Christopher Smith, <i>The Daily Times</i> (Farmington, NM), August 17, 2009</div align=right><br><br />
<br />
-----<br />
<br />
<blockquote>Formulated by Godwin way back in 1990 when the Internet was truly the domain of geeks, [Godwin's law] states that "As an online discussion continues, the probability of a reference or comparison to Hitler or to Nazis approaches 1.</blockquote><br />
<div align=right>Rick Casey, <i>Houston Chronicle</i>, August 14, 2009</div align=right><br><br />
<br />
<br />
A brief <i>Wall Street Journal</i> article [http://blogs.wsj.com/health/2009/08/11/is-the-mediterranean-diet-good-for-your-brain/] summarized a JAMA report about two recent studies of the relationship between the Mediterranean Diet and cognitive decline. Apparently an (undated) older study had suggested the existence of a relationship.<br><br />
<br />
One of the two recent studies involved 2,000 elderly people and found that “those who adhered more closely to a Mediterranean diet … had less risk of developing [dementia].” The other study, from France, involved 1,410 people and found that “[a]dherence to the diet didn’t change the risk of dementia.”<br><br />
<br />
JAMA’s editorial conclusion:<br />
<blockquote>[A]ll told, there is “moderately compelling evidence that adherence to the Mediterranean-type diet is linked to less late-life cognitive impairment.”</blockquote><br />
<br />
------<br />
<blockquote>Thomas Bayes … was … also the mathematician who formulated a probability theorem that can be used to solve problems that stymie conventional statistics. The crux of his theorem can be stated as follows:<br><br />
The probability of any event is the ratio between the value at which an expectation depending on the happening of the event ought to be computed, and the value of the thing expected upon its happening.</blockquote><br />
<div align=right>[http://www.sciencecentric.com/news/article.php?q=09032738-statistical-road-safety “Statistical road safety”], <i>Science Centric</i>, March 27, 2009</div align=right><br><br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br><br><br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br><br />
<br />
Dinner meeting, 240 minutes, $2,000<br>br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br><br />
Conference call, 90 minutes, $890.63<brbr><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Submitted by Paul Alper<br><br />
<br />
==Defining a clunker==<br />
[http://online.wsj.com/article/SB124940692698405243.html “When Precision Is Only 92.11567% Accurate”]<br><br />
by Charles Forelle, <i>The Wall Street Journal</i>, August 5, 2009<br> <br />
<br />
Temporarily substituting for Carl Bialik (The Numbers Guy), Forelle reports about the government’s cash-for-clunkers program and critiques the EPA’s recently revised definition of a clunker.<br> <br />
<br />
The EPA stated that “more precise” data calculated “to four decimal places” led it to revise its miles-per-gallon cutoff figures.<br />
<blockquote>"It is ludicrous to suggest that you can get fuel-consumption accuracy anywhere past the first decimal place, let alone the second," says … an independent U.K. auto tester.</blockquote><br />
<br />
Forelle discusses the “faux precision” of estimates that are often based on sampling, but reported as final counts or measurements without their sometimes large margins of error, as in the case of population or unemployment-rate estimates.<br><br />
<br />
He cites another issue involved in misleadingly precise estimates, that is, lack of adherence to conventional rules relating to the issue of significant figures in arithmetic.<br />
<br />
<blockquote>The principle is simple: When combining measured numbers, the final answer is only as precise the least-precise piece of data that went into it; you can't just add a tail of decimal places, even if they show up on the calculator. So a room that's 2.5 meters (two significant digits) by 3.87 meters (three) has an area of 9.7 square meters, though the two numbers multiply to 9.675.</blockquote><br />
<br />
Fuel mileage calculations are apparently based upon tailpipe emissions of carbon dioxide, because released carbon dioxide from burning fuel provides a more accurate measure of gas consumption than direct measurement of consumed fuel. Not only does the EPA believe that the results of two lab tests on each car must be recorded to four decimal places by law, but it also added tests that were not done on older cars, and “created a formula that estimated from the old data what would happen had the new tests been run,” this despite the different precision levels of numbers that went into the formulas. An EPA spokesman said, "Repeatability and accuracy is something we spend a lot of time on."<br><br />
<br />
Discussion<br><br />
<br />
1. What’s the difference between accuracy and precision?<br><br />
<br />
2. How do you count significant digits in numbers, or report correctly in arithmetic results? (Two websites, un-vetted by contributor, may be of interest [http://en.wikipedia.org/wiki/Significant_figures] or [http://www.physics.uoguelph.ca/tutorials/sig_fig/SIG_dig.htm].)<br><br />
<br />
3. A blogger commented [http://online.wsj.com/article/SB124940692698405243.html#articleTabs%3Dcomments], “Regards your room area example, if both length and width are measured by a person who makes the same direction of error on each measurement -- so that both are either too high or too low -- then the area will not only have almost twice the percentage error of either measurement, it will, on average be too high.” Do you agree with all, or part of, this statement?<br><br />
<br />
4. The author described a 1991 court case in which an Alaskan man failed a bar exam and “missed by 0.5 point the threshold needed for a re-evaluation of his test.” The man claimed that, since the essays were graded with integers, his score should have been rounded up to the next integer. Although the man lost the case, the Alaska Supreme Court found his argument “convincing from a purely mathematical standpoint.” A blogger argued [http://online.wsj.com/article/SB124940692698405243.html#articleTabs%3Dcomments] that there are an infinite number of significant digits in counts (<i>e.g.</i>, 1.000…), because “the error in the value of these numbers is ZERO,” and so arithmetic results “can be rounded to as many sig figures as you want to.” Do you agree with the Alaskan man or with the blogger?<br><br />
<br />
==All that jazz==<br />
[http://online.wsj.com/article/SB10001424052970204619004574320303103850572.html “Can Jazz Be Saved?”]<br><br />
by Terry Teachout, <i>The Wall Street Journal</i>, August 9, 2009<br><br />
<br />
Based on the National Endowment of the Arts’ 2008 Survey of Public Participation in the Arts [http://arts.endow.gov/news/news09/SPPA-highlights.html], popular interest in jazz on the part of adult Americans appears to be experiencing a serious decline. The study was conducted “in participation with” the U.S. Census Bureau.<br><br />
<br />
Several causes for concern about the future of jazz are a general decrease in attendance in at least one jazz performance per year (down from about 11% to 8% for the period 2002-2008) and an increase in the median age of those who do attend (up from 29 to 46 years for the period 1982-2008).<br><br />
<br />
Supplementary materials [http://arts.endow.gov/research/SPPA/index.html] include a brochure, trend tables (1982-2008), survey instrument, data user’s guide with information on the survey design and procedures, and raw data file.<br><br />
<br />
==Irresponsible data mining==<br />
[http://online.wsj.com/article/SB124967937642715417.html “Data Mining Isn’t a Good Bet For Stock-Market Predictions”]<br><br />
by Jason Zweig, <i>The Wall Street Journal</i>, August 8, 2009<br><br />
<br />
Columnist Jason Zweig discusses “quantitative money manager” David Leinweber’s new book, <i>Nerds on Wall Street: Math, Machines and Wired Markets</i> [http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471369462.html] (Wiley, June 2009).<br><br />
<br />
In his book, Leinweber “dissects the shoddy thinking that underlies most of [the quantitative] techniques” in use today, and he refers to data-mined numbers as “one of the leading causes of the evaporation of money.” <br><br />
<br />
Zweig describes how Leinweber decided to satirize data mining with an example, meant to be a joke. He found that annual butter production in Bangladesh “explained” 75% of the variation in the annual returns of S&P 500-stock index over a 13-year period.<br> <br />
<br />
<blockquote>By tossing in U.S. cheese production and the total population of sheep in both Bangladesh and the U.S., Mr. Leinweber was able to "predict" past U.S. stock returns with 99% accuracy.</blockquote><br />
<br />
Leinweber has advice for avoiding “falling into a data mine”: (a) Check that the results make sense; (b) Check that the claim still holds for smaller subsets of the data; (c) Check the results after costs, fees, and taxes are subtracted; (d) Wait to see if the claim continues to hold true as time goes by.<br><br />
<br />
Students may enjoy a 4-minute video [http://online.wsj.com/article/SB124967937642715417.html#] of Jason Zweig interviewing <i>Nerds</i> author David Leinweber. Or they may be interested in YouTube videos (8 minutes, in four parts) [http://www.youtube.com/results?feature=moby&search_query=nerds+on+wall+street&search_type=&aq=f] ] of a lecture by David Leinweber.<br> <br />
<br />
<b>Discussion</b><br><br />
<br />
The article contained a chart [http://online.wsj.com/article/SB124967937642715417.html] showing the “Correlation of Super Bowl wins by original NFL teams with positive return[s] for the S&P 500.” The bar chart shows the S&P 500 return for each year 1967 through August 6, 2009, with 32 blue bars for years in which a “correlation held” and 11 red bars for years in which it did not.<br><br />
<br />
1. What do you think the chart’s author meant by stating that a “correlation held”? What else would you like to know about his/her “correlation”?<br><br />
<br />
2. Suppose there were a positive correlation, even a relatively high one, between NFL Super Bowl team wins and positive S&P 500 returns. Would you be surprised that Super Bowl wins did not predict positive S&P returns for <i>every one</i> of the years?<br><br />
<br />
==Football: How about a “time-in”?==<br />
[http://www.boston.com/bostonglobe/ideas/articles/2009/08/16/a_modest_proposal_for_improving_football_the_time_in/ “Start the clock: A modest proposal for improving football: the 'time-in'”]<br><br />
by Samuel Arbesman, <i>Boston Globe</i>, August 16, 2009<br><br />
<br />
The author, a postdoctoral fellow at Harvard Medical School, proposes a new football rule - the “time-in” - which would force the game clock to resume. He would limit its use to once per game per team.<br> <br />
<br />
<blockquote>The possibility of a sudden time-in would loom large in every coach’s mind at the most tense points in the game, introducing just enough concern and uncertainty to make the game different.</blockquote><br />
On his website Advanced NFL Stats [http://www.advancednflstats.com/], Brian Burke has developed a mathematical model for computing the probability of victory for a team during a game. According to Burke, the time-in would “only be used by the leading team on defense near the end of the game when there’s a small point difference.” In that case, his prediction is that the time-in “could produce up to a one-third drop in win probability for the losing team.”<br> <br />
<br />
On the other hand, if the time-in has not yet been used during a game, it could be a potential threat to an opposing team, who might have to face the “Unexpected Hanging paradox”:<br />
<blockquote>Imagine a prisoner is told that sometime during the next week he will be hanged, and it will be a complete surprise. The prisoner … reasons thus: I can’t be hanged on Friday, because it’s the final day of the week, and therefore not unexpected. So, I can only be hanged sometime between Monday and Thursday. However, it can’t be Thursday, because now that’s the last possible day to be hanged, and so it won’t be a surprise then either. Continuing this train of thought, the prisoner coolly deduces that he can’t be hanged any day of the week at all, and therefore will not die. He is therefore quite surprised when he is woken up early on Wednesday and sent to his death.</blockquote><br />
The author feels that the surprise element of a time-in would provide more excitement for fans.<br><br />
He cites John Reed’s <i>Clock Management</i>[http://www.johntreed.com/FCM.html] as “the authoritative ... book on time in football.”<br><br />
<br />
==Pre-schoolers understand probability?==<br />
[http://www.nytimes.com/2009/08/16/opinion/16gopnik.html?_r=1&scp=1&sq=your%20baby%20is%20smarter&st=cse “Your Baby Is Smarter Than You Think”]<br><br />
by Alison Gopnik, <i>The New York Times</i>, August 15, 2009<br><br />
[http://women.timesonline.co.uk/tol/life_and_style/women/families/article6793658.ece “Babies’ brains are more sophisticated than we ever believed”]<br><br />
by Alison Gopnik, [UK]<i>Times Online</i>, August 15, 2009<br><br />
<br />
The author is a professor of psychology at Berkeley and author of <i>The Philosophical Baby</i>[http://tol.tbpcontrol.co.uk/TBP.Direct/PurchaseProduct/OrderProduct/CustomerSelectProduct/FullProductDetail.aspx?d=tol&s=C&r=10000414&ui=0&bc=0&productId=13893171&backURL=%2ftbp.direct%2fpurchaseproduct%2forderproduct%2fcustomerselectproduct%2fadvancedsearch.aspx%3fd%3dtol%26s%3dC%26r%3d10000414%26ui%3d0%26bc%3d0%26formEvent%3dSearch].<br><br />
<br />
She describes three recent experiments that show that “even the youngest children have sophisticated and powerful learning abilities” and “show how brilliant a baby’s mind really is.”<br><br />
<br />
In 2008 researchers at the University of British Columbia “proved that babies could understand probabilities.” One-year-old babies were shown a box that contained red balls (20%) and white balls (80%). The babies appeared more surprised (“looked longer and more intently at the experimenter”) when an experimenter pulled a sample of mostly red balls (80%) from the box of mostly white balls. <br />
<blockquote>The babies concluded that the researcher must like the red balls more than the white ones as when she held out her hand, they gave her a red ball rather than a white one. Far from being illogical and egocentric they could learn from statistics and use the logic of what they saw to figure out what someone else wanted.</blockquote><br />
<br />
In 2007 researchers at M.I.T. “demonstrated that when young children play, they are also exploring cause and effect.” <br />
<blockquote>One group [of pre-schoolers] was shown that when you pressed one lever, the duck appeared and when you pressed the other, the puppet popped up. The second group observed that when you pressed both levers at once, both objects popped up, but they never got a chance to see what the levers did separately, which left mysterious the causal relation between the levers and the pop-up objects.</blockquote><br />
When the children were subsequently given the toys to play with, the latter group were more interested in playing with it and “just by playing around, they figured out how it worked.”<br><br />
<br />
In 2007 the author, at Berkeley, “discovered that pre-schoolers can use probabilities to learn how things work.” The children were shown two blocks that could light up a machine, with a yellow one making the machine light up 2 out of 3 times and a blue block making it light up only 2 out of 6 times. When the children were given the blocks and asked to light up the machine, they were more likely to chose the yellow block.<br />
<blockquote>These astonishing capacities for statistical reasoning, experimental discovery and probabilistic logic allow babies to rapidly learn all about the particular objects and people surrounding them.</blockquote><br />
The author also advocates letting babies experiment through play, developing their “capacity for statistical reasoning, experimental discovery and logic,” rather than enrolling them in programs and buying products that claim to “make their babies even smarter.”<br><br />
<br />
A blogger [http://women.timesonline.co.uk/tol/life_and_style/women/families/article6793658.ece] commented:<br><br />
<blockquote>In the experiment you mention with the red and white pinpong balls. It would be interesting to know if the results were the same when the colors were switched, or was it simply a question of the color red?<br />
</blockquote><br><br />
<br />
==Poisson performance in sports==<br />
[http://www.sciencecentric.com/news/article.php?q=09060472-the-first-goal-is-the-deepest “The first goal is the deepest”]<br><br />
<i>Science Centric</i>, June 4, 2009<br><br />
<br />
Two researchers at Canada’s Royal Military College were interested in whether an athletic team that scores the first goal has an improved chance of winning a game.<br> <br />
<br />
They have constructed a formula that gives a team's probability of winning, based on game time remaining after the first goal is scored. Their model includes: (a) a weighting to account for overtime; (b) the assumption, which is true for hockey and soccer, that the number of goals scored follows a Poisson distribution; (c) parameters for league position and seasonal performance.<br><br />
<br />
It appears from the article that the first-goal team has an increasingly better chance of victory the longer it takes it to score that goal.<br><br />
<br />
The researchers are less interested in predicting sports outcomes than they are in providing an example for statistics students of probability trees and several probability distributions.<br><br />
<br />
==Pay-to-play online auction==<br />
[http://www.nytimes.com/2009/08/17/technology/internet/17shop.html?_r=1&hpw “Sites Ask Users to Spend to Save”] <br><br />
by Brad Stone, <i>The New York Times</i>, August 16, 2009<br><br />
<br />
<i>Swoopo</i> [http://www.swoopo.com/] is a “seductive and controversial” website for online shoppers. For 60 cents per bid, potential customers are said to be able to win a wide range of retail products at unbelievably low prices.<br><br />
<br />
Bidding starts at $0.00, can increase by as little as 1 cent, and the fee for each bid is $0.60. Also, to avoid users grabbing an item at the last minute, a few seconds are added to the clock with every new bid.<br><br />
<br />
Recently someone won a $1500 LG refrigerator for about $80; however, fees from all bidders totaled more than $2300 for that item.<br> <br />
<br />
Some criticisms of <i>Swoopo</i> are (a) it can be addictive, preying on people’s tendency to “overlook the small increments of money they spend to pursue alluring discounts”; (b) the odds are against the players, who number 2.5 registered users from the U.S., Britain, and Germany; (c) <i>Swoopo</i>’s profits are very high; (d) the bidding process lasts much longer than it appears due to seconds being added to the clock throughout the process.<br><br />
<br />
A mathematician and former quantitative hedge fund analyst states:<br />
<br />
<blockquote>In aggregate, consumers trying to obtain these products are overpaying …. Unless you have an edge over other people who are bidding, and you can get them to subsidize your purchase, you shouldn’t do it. It’s a chump’s game.</blockquote><br />
<br />
<i>Swoopo</i>’s chief executive counters:<br />
<br />
<blockquote>We are combining elements of online auctions, skill games and traditional e-commerce …. We are trying to bring back fun and excitement into shopping, which hasn’t been there in a long time.</blockquote><br />
<br />
One recent customer won a new refrigerator for less than $10, having spent more than $60 on bids. However, she reports that “she has lost far more auctions than she has won, and that there does not appear to be a way to gain a persistent edge over rival bidders.”<br><br />
<br />
Another customer admitted that he had “spent more money in a winning effort than the item itself would have cost.” <br />
<br />
<blockquote>You have to have some skill at it, or you are not going to go anywhere …. I wouldn’t call it gambling at all.</blockquote><br />
<br />
A lawyer hired by <i>Swoopo</i> stated:<br />
<blockquote>Lotteries are games of chance, and an auction does not have what you would call any systematic chance, a random event that determines the winner.</blockquote></div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8588Chance News 532009-08-16T02:45:50Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
From [http://www.imbs.uci.edu/Stern.pdf Bayesian statistics for experimental scientists] written by Hal Stern, Department of Statistics, University of California, Irvine:<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (Biometrical Interpretation, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
Submitted by Paul Alper<br><br><br />
-----<br />
From a <i>Wall Street Journal</i> article [http://online.wsj.com/article/SB10001424052970203674704574334752489414792.html] describing the results of a number of research studies about victims of investment fraud:<br />
<blockquote>The typical investment-scam victim is an optimistic married man in his later 50s who has a higher-than-average knowledge of financial matters and deep confidence in his own judgment …. </blockquote><br />
<blockquote> [A man told] an FTC fraud forum that he preferred speaking with a man because "you can lather him up and push all the green buttons." Women were more cautious and asked too many questions, he said, prompting an office maxim, "Don't pitch to the b—."</blockquote><br />
-----<br />
<blockquote> NYT headline: "For Todays Graduate, Just One Word: Statistics" </blockquote> <br />
<div align=right> New York Times <BR><br />
Steve Lohr<BR><br />
August 5, 2009</div align=right><br />
You can read the article [http://www.nytimes.com/2009/08/06/technology/06stats.html?hp Here].<br />
<br />
The article is about the Joint Statistical Meetings in Washington this week and how the job market for statisticians is booming. Here is the accompanying picture:<br />
<br />
http://graphics8.nytimes.com/images/2009/08/06/business/stats2_190.jpg<br />
<br />
==Forsooths==<br />
<br />
A brief <i>Wall Street Journal</i> article [http://blogs.wsj.com/health/2009/08/11/is-the-mediterranean-diet-good-for-your-brain/] summarized a JAMA report about two recent studies of the relationship between the Mediterranean Diet and cognitive decline. Apparently an (undated) older study had suggested the existence of a relationship.<br><br />
<br />
One of the two recent studies involved 2,000 elderly people and found that “those who adhered more closely to a Mediterranean diet … had less risk of developing [dementia].” The other study, from France, involved 1,410 people and found that “[a]dherence to the diet didn’t change the risk of dementia.”<br><br />
<br />
JAMA’s editorial conclusion:<br />
<blockquote>[A]ll told, there is “moderately compelling evidence that adherence to the Mediterranean-type diet is linked to less late-life cognitive impairment.”</blockquote><br />
<br />
------<br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br />
Dinner meeting, 240 minutes, $2,000<br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br />
Conference call, 90 minutes, $890.63<br><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Submitted by Paul Alper<br><br />
<br />
==Defining a clunker==<br />
[http://online.wsj.com/article/SB124940692698405243.html “When Precision Is Only 92.11567% Accurate”]<br><br />
by Charles Forelle, <i>The Wall Street Journal</i>, August 5, 2009<br> <br />
<br />
Temporarily substituting for Carl Bialik (The Numbers Guy), Forelle reports about the government’s cash-for-clunkers program and critiques the EPA’s recently revised definition of a clunker.<br> <br />
<br />
The EPA stated that “more precise” data calculated “to four decimal places” led it to revise its miles-per-gallon cutoff figures.<br />
<blockquote>"It is ludicrous to suggest that you can get fuel-consumption accuracy anywhere past the first decimal place, let alone the second," says … an independent U.K. auto tester.</blockquote><br />
<br />
Forelle discusses the “faux precision” of estimates that are often based on sampling, but reported as final counts or measurements without their sometimes large margins of error, as in the case of population or unemployment-rate estimates.<br><br />
<br />
He cites another issue involved in misleadingly precise estimates, that is, lack of adherence to conventional rules relating to the issue of significant figures in arithmetic.<br />
<br />
<blockquote>The principle is simple: When combining measured numbers, the final answer is only as precise the least-precise piece of data that went into it; you can't just add a tail of decimal places, even if they show up on the calculator. So a room that's 2.5 meters (two significant digits) by 3.87 meters (three) has an area of 9.7 square meters, though the two numbers multiply to 9.675.</blockquote><br />
<br />
Fuel mileage calculations are apparently based upon tailpipe emissions of carbon dioxide, because released carbon dioxide from burning fuel provides a more accurate measure of gas consumption than direct measurement of consumed fuel. Not only does the EPA believe that the results of two lab tests on each car must be recorded to four decimal places by law, but it also added tests that were not done on older cars, and “created a formula that estimated from the old data what would happen had the new tests been run,” this despite the different precision levels of numbers that went into the formulas. An EPA spokesman said, "Repeatability and accuracy is something we spend a lot of time on."<br><br />
<br />
Discussion<br><br />
<br />
1. What’s the difference between accuracy and precision?<br><br />
<br />
2. How do you count significant digits in numbers, or report correctly in arithmetic results? (Two websites, un-vetted by contributor, may be of interest [http://en.wikipedia.org/wiki/Significant_figures] or [http://www.physics.uoguelph.ca/tutorials/sig_fig/SIG_dig.htm].)<br><br />
<br />
3. A blogger commented [http://online.wsj.com/article/SB124940692698405243.html#articleTabs%3Dcomments], “Regards your room area example, if both length and width are measured by a person who makes the same direction of error on each measurement -- so that both are either too high or too low -- then the area will not only have almost twice the percentage error of either measurement, it will, on average be too high.” Do you agree with all, or part of, this statement?<br><br />
<br />
4. The author described a 1991 court case in which an Alaskan man failed a bar exam and “missed by 0.5 point the threshold needed for a re-evaluation of his test.” The man claimed that, since the essays were graded with integers, his score should have been rounded up to the next integer. Although the man lost the case, the Alaska Supreme Court found his argument “convincing from a purely mathematical standpoint.” A blogger argued [http://online.wsj.com/article/SB124940692698405243.html#articleTabs%3Dcomments] that there are an infinite number of significant digits in counts (<i>e.g.</i>, 1.000…), because “the error in the value of these numbers is ZERO,” and so arithmetic results “can be rounded to as many sig figures as you want to.” Do you agree with the Alaskan man or with the blogger?<br><br />
<br />
==All that jazz?==<br />
[http://online.wsj.com/article/SB10001424052970204619004574320303103850572.html “Can Jazz Be Saved?”]<br><br />
by Terry Teachout, <i>The Wall Street Journal</i>, August 9, 2009<br><br />
<br />
Based on the National Endowment of the Arts’ 2008 Survey of Public Participation in the Arts [http://arts.endow.gov/news/news09/SPPA-highlights.html], popular interest in jazz on the part of adult Americans appears to be experiencing a serious decline. The study was conducted “in participation with” the U.S. Census Bureau.<br><br />
<br />
Several causes for concern about the future of jazz are a general decrease in attendance in at least one jazz performance per year (down from about 11% to 8% for the period 2002-2008) and an increase in the median age of those who do attend (up from 29 to 46 years for the period 1982-2008).<br><br />
<br />
Supplementary materials [http://arts.endow.gov/research/SPPA/index.html] include a brochure, trend tables (1982-2008), survey instrument, data user’s guide with information on the survey design and procedures, and raw data file.<br><br />
<br />
==Irresponsible data mining==<br />
[http://online.wsj.com/article/SB124967937642715417.html “Data Mining Isn’t a Good Bet For Stock-Market Predictions”]<br><br />
by Jason Zweig, <i>The Wall Street Journal</i>, August 8, 2009<br><br />
<br />
Columnist Jason Zweig discusses “quantitative money manager” David Leinweber’s new book, <i>Nerds on Wall Street: Math, Machines and Wired Markets</i> [http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471369462.html] (Wiley, June 2009).<br><br />
<br />
In his book, Leinweber “dissects the shoddy thinking that underlies most of [the quantitative] techniques” in use today, and he refers to data-mined numbers as “one of the leading causes of the evaporation of money.” <br><br />
<br />
Zweig describes how Leinweber decided to satirize data mining with an example, meant to be a joke. He found that annual butter production in Bangladesh “explained” 75% of the variation in the annual returns of S&P 500-stock index over a 13-year period.<br> <br />
<br />
<blockquote>By tossing in U.S. cheese production and the total population of sheep in both Bangladesh and the U.S., Mr. Leinweber was able to "predict" past U.S. stock returns with 99% accuracy.</blockquote><br />
<br />
Leinweber has advice for avoiding “falling into a data mine”: (a) Check that the results make sense; (b) Check that the claim still holds for smaller subsets of the data; (c) Check the results after costs, fees, and taxes are subtracted; (d) Wait to see if the claim continues to hold true as time goes by.<br><br />
<br />
Students may enjoy a 4-minute video [http://online.wsj.com/article/SB124967937642715417.html#] of Jason Zweig interviewing <i>Nerds</i> author David Leinweber. Or they may be interested in YouTube videos (8 minutes, in four parts) [http://www.youtube.com/results?feature=moby&search_query=nerds+on+wall+street&search_type=&aq=f] ] of a lecture by David Leinweber.<br> <br />
<br />
<b>Discussion</b><br><br />
<br />
The article contained a chart [http://online.wsj.com/article/SB124967937642715417.html] showing the “Correlation of Super Bowl wins by original NFL teams with positive return[s] for the S&P 500.” The bar chart shows the S&P 500 return for each year 1967 through August 6, 2009, with 32 blue bars for years in which a “correlation held” and 11 red bars for years in which it did not.<br><br />
<br />
1. What do you think the chart’s author meant by stating that a “correlation held”? What else would you like to know about his/her “correlation”?<br><br />
<br />
2. Suppose there were a positive correlation, even a relatively high one, between NFL Super Bowl team wins and positive S&P 500 returns. Would you be surprised that Super Bowl wins did not predict positive S&P returns for <i>every one</i> of the years?<br></div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8472Chance News 532009-08-06T16:56:43Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (Biometrical Interpretation, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
These quotations occur in<BR> <br />
[http://www.imbs.uci.edu/Stern.pdf Bayesian statistics for experimental scientists] written by Hal Stern, Department of Statistics, University of California, Irvine.<br />
<br />
Submitted by Paul Alper<br />
<br />
==Forsooths==<br />
<br />
<br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br />
Dinner meeting, 240 minutes, $2,000<br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br />
Conference call, 90 minutes, $890.63<br><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8453Chance News 532009-08-05T15:45:25Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (Biometrical Interpretation, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
These quotations occur [http://www.imbs.uci.edu/Stern.pdf here] in<BR> <br />
BAYESIAN STATISTICS FOR<BR><br />
EXPERIMENTAL SCIENTISTS:<BR><br />
ANOVA EXAMPLES<BR><br />
<br />
Hal Stern<BR><br />
Department of Statistics<BR><br />
University of California, Irvine<BR><br />
<br />
The link is [http://www.imbs.uci.edu/Stern.pdf here].<br />
<br />
==Forsooths==<br />
<br />
<br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br />
Dinner meeting, 240 minutes, $2,000<br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br />
Conference call, 90 minutes, $890.63<br><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8450Chance News 532009-08-05T15:42:41Z<p>PaulAlper: /* Kuklo's Fellow Infuse Worker */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (Biometrical Interpretation, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
These quotations occur in<BR> <br />
BAYESIAN STATISTICS FORM<BR><br />
EXPERIMENTAL SCIENTISTS:<BR><br />
ANOVA EXAMPLES<BR><br />
<br />
Hal Stern<BR><br />
Department of Statistics<BR><br />
University of California, Irvine<BR><br />
<br />
The link is [http://www.imbs.uci.edu/Stern.pdf here].<br />
<br />
==Forsooths==<br />
<br />
<br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br />
Dinner meeting, 240 minutes, $2,000<br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br />
Conference call, 90 minutes, $890.63<br><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_53&diff=8449Chance News 532009-08-05T15:40:54Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>If they would only do as he did and publish posthumously<BR><br />
we should all be saved a lot of trouble</blockquote><br />
<div align=right> M. G. Kendall (JRSS A131, p. 185)<BR> in reference to<br />
followers of Rev. T. Bayes</div align=right><br />
<br />
<blockquote>If your experiment needs Bayesian statistics, <BR>you ought<br />
to have done a better experiment</blockquote><br />
<br />
<div align=right> Slight change to a quote of<BR><br />
N. Gilbert (Biometrical Interpretation, 1973)<BR><br />
Attributed there to Lord Rutherford</div align=right><br />
<br />
These quotations occur in<BR> <br />
BAYESIAN STATISTICS FORM<BR><br />
EXPERIMENTAL SCIENTISTS:<BR><br />
ANOVA EXAMPLES<BR><br />
<br />
Hal Stern<BR><br />
Department of Statistics<BR><br />
University of California, Irvine<BR><br />
<br />
The link is [http://www.imbs.uci.edu/Stern.pdf here].<br />
<br />
==Forsooths==<br />
<br />
<br />
<br />
==Kuklo's Fellow Infuse Worker==<br />
<br />
From [http://www.twincities.com/business/ci_12954917?nclick_check=1 The Pioneer Press] we learn that there is more to the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_50#More_on_Infuse_and_Kuklo_II Kuklo story]. "Dr. David Polly, the University of Minnesota spine surgeon ... received nearly $1.2 million in consulting fees from medical device giant Medtronic over a five-year period." The details "of Polly's billing records were released this week by Sen. Charles Grassley, R-Iowa, as an attachment to a letter to University of Minnesota President Robert Bruininks. The letter raised questions about how the U polices conflicts of interest among doctors."<br />
<br />
Polly's recordkeeping was indeed detailed: <br />
<br />
Download CDs from meeting, 15 minutes, $125<br><br />
Dinner meeting, 240 minutes, $2,000<br><br />
E-mail Medtronic employee, five minutes, $49.48<br><br />
Conference call, 90 minutes, $890.63<br><br />
Teach at scoliosis meeting, 330 minutes, $2,750<br><br />
<br />
According to the newspaper, Dr. Charles Rosen, a spine surgeon in California who leads a medical ethics group, said he was among those surprised by the details.<br />
<br />
"I've not seen anybody bill the way he did," said Rosen, of the University of California-Irvine, who acknowledged that he doesn't do paid consulting work with the device industry.<br />
<br />
"In my opinion, it sounds more like an investment banker," he said of the detailed billing. "It doesn't sound like someone in medicine."<br />
<br />
Sumitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_52&diff=8214Chance News 522009-07-11T15:59:54Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Correlation coefficients are now about as ubiquitous <br>and unsurprising as cockroaches in New York City.</blockquote><br />
<br />
<div align=right> In Stephen Jay Gould's <i>The Mismeasure of Man</i>,<br> Second edition, 1996, Page 286. </div align=right><br />
<br />
==Forsooths==<br />
<br />
<br />
==Item 1==<br />
<br />
==item 2==<br />
<br />
==item 3==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_51&diff=8316Chance News 512009-07-11T15:58:46Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Passion is inversely proportional to the amount of real information available.</blockquote><div align=right>Gregory Benford, <i>Timescape</i>, 1980</div align=right><br />
<br />
-----<br />
Re remark about the “attitudes and prejudices of the famous philosophers” in Chance News 49 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49], a 1924 Virginia sterilization law (not repealed until 1976) was upheld by the Supreme Court in <i>Buck v. Bell</i> in 1927, with Justice Oliver Wendell Holmes Jr. writing the majority opinion.<br><br />
<blockquote>“This woman [Carrie Bell] got railroaded. And one of the giants of the Supreme Court was driving the train.”</blockquote><br />
<div align=right>Paul Lombardo, quoted in "Terrible legacy of U.S. eugenics" [http://www.usatoday.com/news/health/2009-06-23-eugenics-carrie-buck_N.htm]<br><i>USA TODAY</i>, June 24, 2009</div align=right><br><br />
<br />
-----<br />
<blockquote>Much of the fascination of statistics lies embedded in our gut feeling--and never trust a gut feeling--that abstract measures summarizing large tables of data must express something more real and fundamental than the data themselves. (Much professional training in statistics involves a conscious effort to counteract this gut feeling.) The technique of ''correlation'' has been particularly subject to such misuse because it seems to provide a path for inferences about causality (and indeed it does, sometimes--but only sometimes).</blockquote><br />
<br />
<div align=right>Page 269 in Stephen Jay Gould's <i>Mismeasure of Man</i>, 2nd edition, 1996 </div align=right><br />
Submitted by Paul Alper<br />
<br />
==Forsooths==<br />
<br />
<blockquote>…. Let’s look at basketball …. The 1993 college basketball playoffs started with 64 teams. Of these, 15 were from schools with accredited library education programs.<br />
That’s an amazing statistic by itself, when you consider that there are only slightly more than three times that many library education programs in the United States, and that some of these don’t compete athletically in Division I. However, those 15 schools also went on to win 28 of the 63 games played, while losing only 14. The reason that there were only 14 losses is that the championship school has a library education program. So does the runnerup. Indeed, what sportswriters call the Final Four included three schools with accredited library education programs.<br><br />
…. Do I believe a single word of what I have just written? Of course not, although I have seen “research” studies … for which the hypotheses were no more credible.</blockquote><br />
<div align=right>Herbert S. White<br><br />
"Is There a Correlation Between Library Education Programs and Athletic Success?<br><i>Library Journal</i>, August 1993</div align=right><br><br />
<br />
-----<br />
During <i>The Daily Show</i> on June 30, TV’s Jon Stewart gave out RIPPY (Rest-In-Peace) Awards [http://www.thedailyshow.com/video/index.jhtml?videoId=232234&title=The-Rippy-Awards-for-Outstanding-Achievement-in-Obitutainment&byDate=true] to television commentators for various aspects of their coverage of Michael Jackson’s death.<br />
<blockquote>It’s the award for attempts at mind-blowing analysis, and the winner is Extra’s Carlos Diaz [who stated on June 25]:<br><br />
People don’t realize the proximity of this whole thing. Farrah Fawcett passed away 5 hours, almost to the minute that Michael Jackson passed away 5 miles away. Ed McMahon passed away 48 hours previous [sic] at the same hospital that Michael Jackson passed away.</blockquote><br />
<br />
==Credit utilization ratio==<br />
[http://www.time.com/time/magazine/article/0,9171,1904129,00.html “Is Your Credit Too Good? Why lenders are punishing those who borrow too little and always pay on time”]<br><br />
by Cybele Weisser, <i>TIME</i>, June 22, 2009<br><br />
<blockquote>[T]he formula for determining credit scores … looks at something called your “utilization ratio,” the total amount of credit you use vs. the amount you have available. If you have $25,000 worth of available credit and you put $5,000 on your cards every month, your utilization ratio is a healthy … 20%. But cut down that credit line to $10,000 and suddenly your ratio jumps to 50%, making you look pretty overextended.</blockquote><br />
<br />
==Student-loan repayment for congressional staffers==<br />
[http://online.wsj.com/article/SB124578152192043001.html#articleTabs%3Dcomments “Scrutiny Grows as U.S. Pays Staffers’ Student Loans”]<br>by Elizabeth Williamson, <i>The Wall Street Journal</i>, June 25, 2009<br><br />
<br />
<blockquote>The House and Senate will spend $18 million this year repaying staffers' student loans. Last year, ... House lawmakers nearly doubled what the government can pay for their staffers' college bills. The yearly maximum repayment is $10,000 in fiscal 2009, which ends Sept. 30, up from $6,000 in fiscal 2008, with a lifetime maximum of $60,000, the same as in the executive branch. The House appropriated $13 million in 2009 for the program; as of last month, more than 2,200 House employees were getting the money.</blockquote><br />
<br />
<center>http://s.wsj.net/public/resources/images/NA-AY547_EXPENS_NS_20090624180410.gif</center><br />
<br />
==Measuring excess risk==<br />
[http://www.usatoday.com/tech/science/environment/2009-06-23-epa-study_N.htm?loc=interstitialskip “EPA study: 2.2M live in areas where air poses cancer risk”]<br>by Brad Heath and Blake Morrison, <i>USA TODAY</i>, June 24, 2009<br><br />
<br />
This article gives a brief report about the National-Scale Air Toxics Assessment for 2002 [http://www.epa.gov/nata2002/factsheet.html], an EPA study of excess cancer risks from breathing 181 air toxics over an assumed lifetime of 70 years. The EPA updates information about air toxics emissions every three years, after which it conducts an analysis which is reviewed by the states, evaluated for accuracy, and released - apparently a long process.<br><br />
<br />
According to the EPA, the study found 2 million people with an increased cancer risk of greater than 100 in 1 million.<br><br />
<br />
According to the article, the study found air pollution to be a health threat “around major cities … although some of the counties where the air was even worse were in rural areas ….” The worst neighborhood was outside Los Angeles, where the estimated excess cancer risk was “more than 1,200 in 1 million, 34 times the national average.” The article provided no information about rural areas; however, the EPA provides a map [http://www.epa.gov/ttn/atw/nata2002/risksum.html] of most affected counties.<br />
<center>http://www.epa.gov/ttn/atw/nata2002/images/NATARisks100inaMil.jpg</center><br />
<br />
Discussion<br><br />
<br />
1. How might one measure <i>cancer risk</i>?<br><br />
<br />
2. What does it mean to measure <i>excess</i>, or <i>increased</i>, cancer risk?<br><br />
<br />
3. Why does the EPA measure excess risk over a <i>lifetime</i>? How do you think they identified people who had lived in a region over a lifetime? Would the fact that air pollution levels might change over a lifetime affect any aspect of the study?<br><br />
<br />
4. Estimate the national average excess cancer risk. Is it higher or lower than the EPA’s ceiling of 100 in 1 million? Do you think it makes sense to refer to a <i>national average</i> of excess cancer risk?<br><br />
<br />
5. Referring to the map, are you surprised about any of the locales with the highest excess cancer risk? If so, can you find any potential reason for high excess cancer risks in those locales?<br><br />
<br />
==Too many cable TV channels?==<br />
[http://online.wsj.com/article/SB124603687047661927.html “Time to Screen Out Unloved Channels”]<br><br />
by Martin Peers, <i>The Wall Street Journal</i>, June 27, 2009<br><br />
(Full text may only be available to subscribers.)<br><br />
<br />
The author suggests that there are too many TV channels available and that this situation is driving subscriber costs up. He reports that "the average household tuned into only 16 channels of the 118 channels available.” He feels that charging fees in proportion to the sizes of viewing audiences would lower the cost of cable TV.<br><br />
He says that there is currently the “absence of correlation between the size of the fees paid to individual cable channels and their audiences.” Among non-premium channels, Nickelodeon was the most-watched cable channel in 2008, but its fees were not the highest (10th from the highest). Nickelodeon, with about 1.7 million daily household viewers, also had an annual affiliate revenue of about $300 per household, while Discovery Kids, with only 20,000 daily household viewers, had an annual affiliate revenue of about $1,900 per household.<br />
<center>http://s.wsj.net/public/resources/images/OB-DY540_TVHERD_NS_20090626193119.gif</center><br><br />
<br />
==True or false?==<br />
<blockquote>One hundred sleuthing statisticians running 100 different tests are about 100 times more likely than a lone investigator to find something fishy.</blockquote><br />
<div align=right>Carl Bialik, [http://online.wsj.com/article/SB124640788035376975.html "Rise and Flaw of Internet's Election-Fraud Hunters"]<br><br />
<i>The Wall Street Journal</i>, July 1, 2009</div align=right><br><br />
<br />
==New lottery study== <br />
[http://www.courant.com/news/connecticut/hc-poor-gamble-scratch-0703jul03c,0,7472516.column “Want False Hope With That Lottery Ticket?”]<br><br />
by Rick Green, <i>The Hartford Courant</i>, July 3, 2009<br><br />
<br />
A taxpayer-funded study by Spectrum Gaming Group [http://www.spectrumgaming.com/] is said to have found “no correlation between lottery sales and poverty.” The study claims that “because most successful lottery retailers were not located in higher poverty neighborhoods, there is no connection between income and ticket sales.”<br><br />
<br />
The Spectrum study contradicts many other studies, including one at Cornell University, where investigators “found ’a strong and positive relationship’ between lottery ticket sales and poverty rates after examining data from 39 states over 10 years.”<br><br />
<br />
The Spectrum study also contradicts a 2002 analysis done by the column’s author, Rick Green, and a colleague. They identified, by zip codes, the locales in which the highest concentrations of winners resided, not the locales in which the highest-selling retailers were located. Not surprisingly, these areas were in the poorest cities of Connecticut.<br><br />
<br />
==30% chance for rain?==<br />
For many, meaning of rain forecast is cloudy at best.<br><br />
[http://www.usatoday.com/weather/research/2009-06-23-precipitation-forecast_N.htm <i>USA TODAY</i>], June 24, 2000<br><br />
Doyle Rice<br><br />
<br />
This news article begins with:<br><br />
<br />
<blockquote>When your local weather forecaster announces that there is a 30% chance of rain tomorrow, not everyone knows what that means. Some think it means 30% of an area will get rain. Others think it will rain for 30% of the day. In fact, of all the forecast terms used by meteorologists, this remains one of the most baffling to the public.<br><br><br />
<br />
Some people don't understand that the forecaster simply means there's a 30% probability it will rain at some point during the day. Susan Joslyn, a senior lecturer in the psychology department at the University of Washington in Seattle, and colleagues have been studying such confusion.</blockquote><br />
<br />
The news article explains the results of this study. There have been many studies like this. The following is a study which is often referred to when the "30% chance of rain problem" is brought up. <br />
<br />
Misinterpretations of Precipitation.<br><br />
Bulletin American Meteorological Society, Vol. 61, No 7, <br><br />
July 1980, p.695-701.<br><br />
Murphy, Licthenstein, Fischoff and Winkler<br><br />
<br />
We reviewed this article in [http://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_3.06.html#Misinterpretations Chance News 3.08] In this review we wrote:<br />
<br />
<blockquote>The authors wanted to see if there was a <br />
misunderstanding about the event being predicted, the <br />
meaning of probability or both. To test the <br />
understanding of the event, subjects were asked if the <br />
event being predicted was "rain somewhere in the <br />
region", "rain at a particular point in the region" <br />
"rain 20% of the time etc. Their answers led the authors <br />
to the conclusion that there is considerable <br />
misinterpretation on the meaning of the event. On the <br />
other hand, the subjects' answers to questions on the <br />
possible meaning of "20% chance" led them to conclude <br />
that the subjects did understand what the probability <br />
itself meant.</blockquote><br />
<br />
I also talked to a couple of meteorologists who stated <br />
that it is unlikely that the public could understand <br />
what a 20% chance of rain means. Harold Brooks<br />
provided the following statement: <br><br />
<br />
<blockquote> According to the National Weather Service Operations Manual, <br />
the Probability of Precipitation (PoP) is <br />
the likelihood of occurrence (expressed as a percent) of a precipitation event <br />
at any given point in the forecast area. <br />
the time period to which the PoP applies <br />
must be clearly stated (or unambiguously <br />
inerferred from the forecast wording) since, <br />
without this, a numerical PoP value is meaningless. That is, it is the average point probability within the forecast area and the same PoP is<br />
assigned to each point. It can be shown that the PoP is equal to the expected area<br />
coverage of the precipitation (Schaefer, J. T. <br />
nd R. L. Livingston, 1990: Operational implications of the "Probability of Precipitation". Weather. Forecasting, 5, 354-356.).</blockquote><br />
<br />
An interesting study by Gerd Gigerenzer and friends can be found [http://www.mpib-berlin.mpg.de/en/mitarbeiter/gigerenzer/pdfs/RainFinal.pdf here]<br />
<br />
In there they write<br />
<br />
<blockquote>The weather forecast says that there is a “30% chance of rain,” and we think we understand what it means. This quantitative statement is assumed to be unambiguous and to convey more information than does a qualitative statement like “It might rain tomorrow.” Because the<br />
forecast is expressed as a single-event probability, however, it does not specify the class of<br />
events it refers to. Therefore, even numerical probabilities can be interpreted by members of<br />
the public in multiple, mutually contradictory ways. To find out whether the same statement<br />
about rain probability evokes various interpretations,we randomly surveyed pedestrians in five<br />
metropolises located in countries that have had different degrees of exposure to probabilistic<br />
forecasts––Amsterdam, Athens, Berlin, Milan, and New York. They were asked what a “30%<br />
chance of rain tomorrow” means both in a multiple-choice and a free-response format. Only in<br />
New York did a majority of them supply the standard meteorological interpretation, namely,<br />
that when the weather conditions are like today, in 3 out of 10 cases there will be (at least<br />
a trace of) rain the next day. In each of the European cities, this alternative was judged as<br />
the least appropriate. The preferred interpretation in Europe was that it will rain tomorrow<br />
“30% of the time,” followed by “in 30% of the area.” To improve risk communication with<br />
the public, experts need to specify the reference class, that is, the class of events to which a<br />
single-event probability refers.</blockquote><br />
<br />
<br />
Our first introduction to this problem apparently was at a two-week summer workshop entitled 'Geometry and the Imagination', taught by Peter Doyle, Mark Foskey, Joan Garfield, Linda Green, and Laurie Snell at the Geometry Center in Minneapolis, 20 June-1 July, 1991. <br />
Despite the name this was a Chance Course.<br />
<br />
Here the participants were asked to read the materials on weather prediction and answer these questions:<br />
<br />
(1) What do you make of all this?<br />
<br />
(2) What does Marilyn means when she says, `But rain doesn't obey the laws of chance; instead it obeys the laws of science.'<br />
<br />
(3) If the PoP is 30% and it rains, was the forecaster correct?<br />
<br />
(4) Suppose that Minneapolis gets precipitation 3 days out of 10 over the long haul. Why not report a PoP of 30% every single day?<br />
<br />
(5) San Diego county is spread out over a large area, comprising the coastal strip and inland valleys, the mountains, and the deserts. Separate forecasts are given for each region. Suppose, however, that the weather bureau computes a single PoP for the whole area. On days on which this composite PoP is 20%,<br />
what is the probability that a randomly selected resident of San Diego county will get rained on?<br />
<br />
(6) What do you think is the correct answer to the Reader reader's question?<br />
<br />
(7) There are contests to reward the best predictor of the weather. If you were running such a contest, how would you decide the winner?<br />
<br />
Readers might like to view two Chance video lectures about weather forecasting: (1) "How are Weather Predictions Determined by the National Weather Service?" [http://www.dartmouth.edu/~chance/ChanceLecture/Nweath/Nweath.htm], by Daniel Wilks, Cornell University; (2) "How are Local Weather Predictions Determined By Local Weather Forecasters?" [http://www.dartmouth.edu/~chance/ChanceLecture/Lweath/Lweath.htm], by Mark Breen, Fairbanks Museum.<br><br />
<br />
Submitted by Laurie Snell<br />
<br />
==Need for evidence==<br />
<br />
[http://www.time.com/time/politics/article/0,8599,1905340,00.html “How to Cut Health-Care Costs: Less Care, More Data”]<br><br />
by Michael Grunwald, <i>TIME</i>, June 29, 2009<br><br />
<br />
According to the author, President Obama has identified two major obstacles to more efficient health care delivery, the first of which is the current “fee-for-service” system in which hospitals and doctors are rewarded financially for ordering more tests and carrying out more procedures.<br />
<blockquote>The other big barrier is information: evidence-based medicine is hard to practice without evidence. …. So the things we know are dwarfed by the things we don’t know. …. [The] Mayo [Clinic] … has an institutional obsession with evidence-based medicine, using electronic records for in-house effectiveness research, constantly monitoring its doctors on everything from infection rates to operating times to patient outcomes, minimizing the art of medicine and maximizing the science. “We try to drive out variation wherever we can,” says Charles (Mike) Harper, a neurologist who oversees Mayo’s clinical practice in Rochester. “Practicing medicine is not the same as building Toyotas, but you can still standardize. Uncertainty shouldn’t be an excuse to ignore data.”</blockquote><br />
<br />
==Billions of almost-zeros==<br />
[http://www.newyorker.com/arts/critics/books/2009/07/06/090706crbo_books_gladwell “Priced to Sell”]<br><br />
by Malcolm Gladwell, <i>The New Yorker</i>, July 6 & 13, 2009<br><br />
<br />
In his new book, <i>Free: The Future of a Radical Price</i>, author Chris Anderson states:<br />
<blockquote>Distribution [of online videos] is now close enough to free to round down. Today, it costs about $0.25 to stream one hour of video to one person. Next year, it will be $0.15. A year later it will be less than a dime. Which is why YouTube’s founders decided to give it away.</blockquote><br />
In this book review, Malcolm Gladwell notes, however:<br />
<blockquote>Although the magic of Free technology means that the cost of serving up each video is “close enough to free to round down,” “close enough to free” multiplied by seventy-five billion is still a very large number.</blockquote><br />
<br />
A critique of Anderson's <i>Free</i>, and Ellen Ruppel's <i>Cheap</i>, can be found in <i>The New York Times</i>, July 5, 2009 [http://www.nytimes.com/2009/07/06/books/06maslin.html?_r=1&hpw].<br><br />
<br />
==Love (food) and marriage?==<br />
[http://www.time.com/time/magazine/article/0,9171,1907143,00.html “First Comes Love, Then Comes Obesity?”]<br><br />
by Bonnie Rochman, <i>TIME</i>, July 6, 2009<br><br />
<br />
This article discusses a University of North Carolina study of the relationship between romance and obesity. Published in the July issue of <i>Obesity</i> , the study found that “married individuals are twice as likely to become obese as are people who are merely dating.” The study “tracked changes over a handful of years in the weight and relationship status of 6,949 individuals.” The effect of increased risk of obesity appears to have affected women more than men, for folks who lived together, whether married or not.<br><br />
<br />
==When in the course of human events ...== <br />
[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Darticle “Two Centuries On, a Cryptologist Cracks a Presidential Code”]<br><br />
by Rachel Silverman, <i>The Wall Street Journal</i>, July 2, 2009<br><br />
<br />
The author reports that Lawren Smithline, a mathematician at the Center for Communications Research in Princeton, NJ, has deciphered a coded message in an 1801 letter to President Thomas Jefferson from a math professor at the University of Pennsylvania.<br><br />
<br />
The code [http://s.wsj.net/public/resources/documents/cipher0701.pdf], was not a “simple substitution cipher,” in which one letter of the alphabet is replaced with another, and so could not be cracked using ordinary frequency analysis. Nor was the code a “nomenclator,” which is a “catalog of numbers, each standing for a word, syllable, phrase or letter,” or a “wheel cipher,” which involves letters inscribed on the edge of a wheel that can be turned to scramble words.<br><br />
<br />
Mr. Patterson claimed “the utter impossibility of deciphering” his code, which involved a grid of the text, broken into sections. He estimated that a de-coder might have to try “upwards of ninety millions of millions” of potential combinations in order to solve his coded message to Jefferson.<br> <br />
<br />
Dr. Smithline analyzed Jefferson’s State of the Union addresses and counted the frequency of every possible pair of letters in the speeches. He used a “dynamic programming” algorithm to test some “educated guesses.” Fewer than 100,000 calculations were needed to solve the cipher.<br><br />
<br />
The following message emerged, a “little joke on Thomas Jefferson,” according to Dr. Smithline:<br />
<br />
<blockquote>In Congress, July Fourth, one thousand seven hundred and seventy six. A declaration by the Representatives of the United States of America in Congress assembled. When in the course of human events ....</blockquote><br />
"Patterson played this little joke on Thomas Jefferson," says Dr. Smithline. "And nobody knew until now."<br><br />
<br />
Two bloggers[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Dcomments] commented.<br><br />
<br />
(a) Ms. Silverman should have mentioned the fact that she picked up the story from the March-April 2009 edition of <i>American Scientist</i>, "A Cipher to Thomas Jefferson" [http://www.americanscientist.org/issues/feature/2009/2/a-cipher-to-thomas-jefferson].<br><br />
<br />
(b) If you'd like to read a fun story in which involves a replacement code, frequency analysis, and buried treasure, see Poe's short story, "The Gold-Bug" [http://www.eapoe.org/works/tales/goldbga2.htm].<br><br />
<br />
==Joltin’ Joe==<br />
[http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#printMode “The Triumph of the Random”]<br><br />
by Leonard Mlodinow, <i>The Wall Street Journal</i>, July 3-5, 2009<br> <br />
<br />
This article discusses “streaks,” especially the 56 consecutive baseball games in which Joe DiMaggio had at least one hit, and people’s intuitions about them. The author [http://www.its.caltech.edu/~len/ ] is a Caltech professor, who wrote <i>The Drunkard’s Walk: How Randomness Rules Our Lives</i>.<br><br />
<br />
<blockquote>[R]andom processes do display periods of order. In a toss of 100 coins, for example, the chances are more than 75% that you will see a streak of six or more heads or tails, and almost 10% that you’ll produce a streak of 10 or more. As a result a streak can look quite impressive even if it is due to nothing more than chance. .... A few years ago Bill Miller of the Legg Mason Value Trust Fund was the most celebrated fund manager on Wall Street because his fund outperformed the broad market for 15 years straight. It was a feat compared regularly to DiMaggio’s, but if all the comparable fund managers over the past 40 years had been doing nothing but flipping coins, the chances are 75% that one of them would have matched or exceeded Mr. Miller’s streak.</blockquote><br />
The author argues that DiMaggio’s streak could have occurred by chance alone, based on DiMaggio’s lifetime batting average of 0.325, and the fact that hundreds of players had been trying for such a streak over a hundred years.<br><br />
<br />
The author points out that there are many factors involved in analyzing baseball streaks, <i>e.g.</i>, variations in batting averages over time. Samuel Arbesman and Stephen H. Strogatz, of Cornell, carried out a 10,000-case computer simulation based on baseball players’ actual statistics from each year 1871-2005. They found that streaks ranged from 39 games to 109 games, with 42% having streaks of DiMaggio’s length or longer.<br><br />
<br />
In discussing people’s misconceptions about streaks, the author cites Thomas Gilovich, Robert Vallone, and Amos Tversky’s paper, “The Hot Hand in Basketball: On the Misperception of Random Sequences.” [http://www.psych.cornell.edu/sec/pubPeople/tdg1/Gilo.Vallone.Tversky.pdf]<br><br />
<br />
Other resources not cited in this article include Thomas Gilovich’s 1998 Chance video lecture "Streaks in Sports" [http://www.dartmouth.edu/~chance/ChanceLecture/streak/streak.htm], and Stephen Jay Gould’s 1988 book review "The Streak of Streaks" [http://www.nybooks.com/articles/4337].<br><br />
<br />
Two bloggers [http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#articleTabs%3] commented:<br><br />
<br />
(a) Strogatz's simulation had Cobb out-hitting DiMaggio 300 out of 10000 times, or 3%. Dunno how long he played, but much longer than 3% of baseball. 10000 "seasons" is a sample 100 times greater than reality.<br><br />
<br />
(b) …. “Don’t give me brilliant generals; give me lucky generals.” –Caesar. …. As a former baseball player, I know how hard it is to get a hit on those days when you're just not feeling it. I don't think coins have those days.<br><br />
<br />
Discussion<br><br />
<br />
1. In a toss of 100 coins, what is the probability of seeing a streak of <i>6 or more heads</i>? Here [http://www.bumblebeagle.org/horsehide/hitstreaks.html] is a website with an applet calculator and an explanation of the reasoning behind the calculations.<br><br />
<br />
2. Show that, in a toss of 100 coins, the probability of seeing a streak of <i>6 or more heads or 6 or more tails</i> is more than 75%.<br><br />
<br />
3. Comment on blogger (a)’s response to the article.<br><br />
<br />
==Confidence intervals as public policy==<br />
[http://www.pbs.org/newshour/bb/education/july-dec07/nclb_08-14.html “School Districts Find Loopholes in No Child Left Behind Law”]<br><br />
PBS TV program, originally aired on August 14, 2007<br><br />
<br />
Note: This PBS program may be two years old; however, it has provided good class discussions for the contributor.<br><br />
<br />
This round table program about the 2002 No Child Left Behind Act covered two important aspects of the national assessment of student progress mandated by this act: (1) each state has the discretion to set its own passing percentages and must raise its bars annually; and (2) states may use a confidence interval to capture the passing percentage of a subgroup of a school system that meets a pre-set minimum size. Discussants were Jim Lehrer (moderator), John Merror (PBS Special Correspondent for Education), Margaret Spellings (U.S. Secretary of Education), Kevin Carey (Education Sector Policy Director), and Chester Finn (Fordham Institute President).<br><br />
<br />
Merrow compared the assessment-of-progress system to 100-meter hurdle events, in which “all the hurdles are the same height.” He stated that 9 states set the early NCLB bars “very close to the ground,” in order to show more progress toward what Finn called the unrealistic national goal of 100 percent proficiency by 2014.<br><br />
<br />
Merrow noted that, unlike hurdle events, states are evaluated by how well traditionally underserved groups of students progress; however, if a subgroup does not meet a minimum size requirement, those results are not reported. Finn estimated that about 2 million minority students are not counted because, as subgroups in various municipalities, their sizes do not warrant reporting results. With the Department of Education’s approval, states can increase their subgroup size and avoid having to report a group’s progress.<br><br />
<br />
Merrow described how schools, unlike athletic event judges, may use confidence intervals to capture a passing percentage for a subgroup, and Carey claims that some margins of error are as large as 30 points.<br><br />
<br />
<blockquote>JOHN MERROW: So if my school scored 30 and passing is 55, but the confidence interval is 30 points, we can say we passed?<br><br />
KEVIN CAREY: Yes.<br><br />
JOHN MERROW: Nearly all states use confidence intervals. In Illinois, 509 schools were saved from failing because confidence intervals added up to 12 points to their scores. </blockquote><br />
<br />
Carey felt that percent-passing scores measured in this way give the public a false impression of the performance of their students.<br><br />
<br />
Spellings defended the Act as the beginning of educational accountability, flawed as it may be, and she foresaw revisions in the requirements.<br> <br />
<br />
Prior to this 2007 PBS program, a 2005 article “State gives schools extra leeway,” in the <i>Milwaukee Journal Sentinel</i>, June 15, reporter Jamaal Abdul-Alim quoted an Illinois education official, “We have to ensure that we are as accurate as we can be…. That’s the reason we’re using a 99% confidence interval as opposed to a 95% confidence interval.” A mathematics professor at the University of Wisconsin-Milwaukee stated, “The charitable way to view this is to say they chose 99% to make sure that anybody who they said was bad, really, really is bad…. The uncharitable way to view this is to say they chose 99% so they would have to say as few people are bad as possible.” A statistician at that university felt that the use of confidence intervals “appears to be reasonable, given the consequences of being flagged as a school failing to make progress.”<br></div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_52&diff=8213Chance News 522009-07-11T15:57:32Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Correlation coefficients are now about as ubiquitous <br>and unsurprising as cockroaches in New York City.</blockquote><br />
<br />
<div align=right> In Stephen Jay Gould's <i>The Mismeasure of Man</i>,<br> Second edition, 1996 Page 286. </div align=right><br />
<br />
==Forsooths==<br />
<br />
<br />
==Item 1==<br />
<br />
==item 2==<br />
<br />
==item 3==</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_50&diff=8147Chance News 502009-07-08T13:46:54Z<p>PaulAlper: /* The Ted Talks */</p>
<hr />
<div>==Quotation==<br />
<br />
<blockquote><br />
Probability is a mathematical discipline whose aims are akins to those, for example, of geometry of analytical mechanics. In each field we must carefully distinguish three aspects of the theory: (a) the formal logical content, (b) the intuitive background, and (c) the applications. The character, and the charm, of the whole structure cannot be appreciated without considering all three aspects in their proper relation.</blockquote><br />
<br />
<div align=right> William Feller<br><br />
An Introduction to Probability Theory and its Applications<br />
</div align=right><br><br />
<br />
This quotation was found at the [http://www.mathcs.carleton.edu/probweb/ Probability Web] which our readers will enjoy.<br />
<br />
==Forsooths==<br />
<br />
Naomi Schaefer Riley writes in the Wall Street Journal of 6/23/09 regarding a Colorado appeals court ruling which declared that "the public interest is advanced more by tenure systems that favor academic freedom over tenure systems that favor flexibility in hiring or firing." She then offers this statement, "Some of the courses taught this year by the professors who sued include American Baseball History and Business Statistics."<br />
<br />
<br />
Paul Alper<br />
-----<br />
This graphic has counter-intuitive coloring.<br />
http://graphics8.nytimes.com/images/2009/06/27/opinion/27blowlarge.jpg<br />
<br />
The accompanying article is<br />
[http://www.nytimes.com/2009/06/27/opinion/27blow.htm here]<br />
<br />
Paul Alper<br />
<br />
==Swine flu pandemonium III==<br />
<br />
[http://www.courant.com/news/custom/topnews/hc-swine-flu-death-0619.artjun19,0,5392611.story "Fourth Connecticut Resident With Swine Flu Dies"] by Arielle Levin Becker, The Hartford Courant, June 19, 2009<br><br />
See Chance News 49 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49] for two earlier stories about the second and third cases of swine flu in Connecticut.<br><br />
<br />
A fourth Connecticut death has been "linked" to swine flu. <br />
<blockquote>The person was between 40 and 49 years old and had underlying medical conditions that increased the risk for serious illness from flu, the state Department of Public health said.</blockquote><br />
<br />
To date there have been 767 confirmed cases of swine flu, 28 of the cases had been hospitalized, and 19 of the hospitalized were from the largest cities. All four deaths occurred in people with other medical problems who were hospitalized at the time of death.<br><br />
<br />
Here is the data to date about Connecticut deaths from swine flu:<br><br />
1 death – 395 confirmed cases – June 4<br><br />
2 deaths – 637 confirmed cases – June 11<br><br />
3 deaths – 693 confirmed cases – June 15<br><br />
4 deaths – 767 confirmed cases – June 17<br><br />
<br />
Discussion<br><br />
<br />
1. Would you advise Connecticut residents to move out of large cities to avoid swine flu? Could the victims have been identified as being from the largest cities because they died in large city hospitals, as opposed to having resided in large cities?<br><br />
2. Would you advise Connecticut residents with swine flu to avoid hospitals?<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Swine flu pandemonium IV==<br />
[http://online.wsj.com/article/SB20001424052970204038304574149682916937774.html “Fever, Chills…and Losses: More Companies Should Be Preparing for an Influenza Pandemic”]<br><br />
by Amin Mawani, The Wall Street Journal, June 22, 2009<br><br />
Employers are urged to prepare for a possibly sizeable increase in employee absenteeism from swine flu, the first pandemic declared by the World Health Organization in 41 years. The World Economic Forum predicts a $500 billion economic impact from the pandemic.<br><br />
<blockquote>The good news is that employee absenteeism—and its financial toll on employers—may be controlled to a large extent with adequate planning and stockpiling of antiviral medication, masks and gowns.</blockquote><br />
<blockquote>The bad news is that few companies have taken steps to protect themselves. A 2007 survey reported at a Harvard Business School conference on pandemic planning found that while 88% of companies seemed prepared to deal with a power disruption and 70% with a technological failure, only 13% were prepared for the kind of labor-force disruption that would come with a pandemic.</blockquote><br />
Companies are advised to use cost-benefit analysis to justify preparedness. A company’s benefits associated with “pandemic preparedness” include “the earnings before interest, taxes, depreciation and amortization … that are preserved because employees aren’t absent. To figure this, managers must establish the contribution employees make to profits. Some of these calculations can get complex ….” A company that is prepared may also have a competitive edge due to reliability in bad times, as well as a reduced likelihood of being liable for negligence in governance.<br><br />
Submitted by Margaret Cibes<br><br />
<br />
==Role of luck in golf==<br />
<br />
[http://online.wsj.com/article/SB10001424052970204119704574236053876659482.html "Winning a Major May Just Be a Matter of Luck"], by Jason Turbow, The Wall Street Journal, June 19, 2009<br><br />
<br />
Using data from every PGA leadership board from 1998 to 2001, two business professors, from University of North Carolina and Dartmouth, have used "cubic spline functions" to try to explain the role of luck in professional golf.<br> <br />
<br />
<blockquote>"If being on the leaderboard at the end of a tournament was due entirely to skill, we would see the same names every week," said [the Dartmouth researcher]."</blockquote><br />
<br />
Their model aims to predict an individual's score in a tournament based on an estimate of the person's "intrinsic skill level independent of variables like course difficulty and variations over time." A golfer with a higher tournament score than predicted was considered to have had good luck; one with a lower score was considered to have had bad luck.<br><br />
<br />
<blockquote>[I]n all the events the researchers studied, Mr. Woods was the only golfer to win a tournament despite suffering from negative luck.</blockquote><br />
<br />
The brief article includes a table [http://online.wsj.com/article/SB10001424052970204119704574236053876659482.html] of expected score, actual score, and "luck factor" for players Tiger Woods, Ernie Els, Vijay Singh, Phil Mickelson, Sergio Garcia, and Jim Furyk, in the 2000 U.S. Open.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Baseball: More education, more victories?==<br />
[http://online.wsj.com/article/SB124511558996917441.html "Who Has the Brainiest Team in Baseball?"], by Jason Turbow, The Wall Street Journal, June 16, 2009<br><br />
<br />
The author studied "30 team media guides" to try to determine whether there is "a correlation between education and victories" in professional baseball. He compared team standings with players' and managers' undergraduate degrees. He found that only about two dozen major league players or managers had undergraduate degrees.<br> <br />
<br />
<blockquote>[T]hree "All-Brains" division leaders -- Oakland, Arizona and Washington -- are in last place in real life, while Texas and the Dodgers were last in their divisions in smarts but first in the standings.</blockquote><br />
<br />
Two bloggers [http://online.wsj.com/article/SB124511558996917441.html#articleTabs%3Dcomments] wrote:<br><br />
<br />
(1) "[A]re these results really surprising? The best teams are the best teams because they have more good players than the other teams. Good players are likely to have been A) so talented at baseball as to have little incentive to work hard at school and B) so dedicated to the sport that academics would have suffered. If you're a marginal major league talent like Breslow, it makes sense to get a degree with better earnings potential. Not so for the Alex Rodriguezes [sic] and Barry Bondses [sic] of the world."<br><br />
<br />
(2) "How about instead of looking at university experience, check out something that almost every player (from the U.S., at least) would have: SAT scores. Surely there is the occasional ballplayer with a stratospheric score who still opts for baseball over college."<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Keeping up with the Joneses by lowering utility bills==<br />
[http://www.theatlantic.com/doc/200907/green-envy “Greening With Envy”], by Bonnie Tsui, The Atlantic, August 2009<br><br />
Robert Cialdini, a social psychologist at Arizona State University, tested 4 different hotel reuse-towels signs to test how well guests responded:<br />
<blockquote>The first sign had the traditional message, asking guests to “do it for the environment.” The second asked guests to “cooperate with the hotel” and “be our partner in this cause” (12 percent less effective than the first). The third stated that the majority of guests in the hotel reused towels at least once during their stay (18 percent more effective). The last message was even more specific: it said that the majority of guests “in this room” had reused their towels. It produced a 33 percent increase in response behavior over the traditional message.</blockquote><br />
As the chief scientist for Positive Energy, Cialdini is now applying what he learned to encouraging utility consumers to conserve energy by letting them know how much energy they use relative to their neighbors. Based on his software’s analysis of a neighborhood’s energy usage, a utility company can send monthly bills to consumers with information about how a particular consumer’s usage compared to that of his/her neighbors. For example, a consumer who used “58 percent less electricity” might receive a row of smiley faces, while one who used “39 percent more” might receive no smiley faces, a notice that it cost him/her $741 extra, and tips for improvement.<br><br />
In Sacramento, <br />
<blockquote>people who received personalized “compared with your neighbors” data on their statements reduced their energy use by more than 2 percent over the course of a year. … [W]ith the pilot sample of 35,000 homes, it’s the equivalent of taking 700 homes off the grid. And the cost to the utility is minor: for every dollar a utility spends on a solar power plant, it produces 3 to 4 kilowatt-hours; for every dollar a utility spends on the energy reports, it saves 10 times that.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==A Probability puzzle==<br />
<br />
The [http://www.msri.org/ Mathematical Science Research Institute] has a monthly newsletter called [http://www.msri.org/communications/emissary/index_html The Emissary].This newsletter has, among other things, puzzles. For the Spring 2009 issue, Puzzle 5 was:<br />
<blockquote><br />
Find three random variables X, Y, Z, each uniformly distributed<br />
on [0, 1], such that their sum is constant. (Since each random variable<br />
has expectation 1 the sum must in fact be 3.)<br />
</blockquote><br />
<br />
To better understand this puzzle, consider the case of two random variables X and Y with X a random choice on 0 to 1 and Y = 1- X. Then the sum of X and Y is the constant 1. <br />
<br />
Comment: This puzzle is due to Thomas Colhurst<br />
<br />
Submitted by Laurie Snell<br />
<br />
==The Ted Talks==<br />
<br />
At the Ted talks [http://www.ted.com/pages/view/id/47 website] we read:<br />
<br />
<blockquote> Each year, the world's leading thinkers and doers gather in for an event many describe as the highlight of their year. Attendees have called it "The ultimate brain spa," "Davos for optimists" and "A four-day journey into the future, in the company of those creating it." This event is called TED, and it's truly a conference like no other.<br><BR><br />
"It was incredible." Malcolm Gladwell <br><br />
"A mind-opening experience." Amy Tan <br><br />
"One of the highlights of my entire life." Billy Graham <br><br />
"I've never experienced anything remotely like it." Jeffrey Katzenberg <br><br />
"The combined IQ of the attendees is incredible." Bill Gates </blockquote><br />
<br />
Of course we are interested in statistics or probability talks. We found two statistics talks, one by Hans Rosling and another by Peter Donnelly. You can listen to Rosling's talk [http://www.ted.com/talks/lang/eng/hans_rosling_shows_the_best_stats_you_ve_ever_seen.html here.]<br />
<br />
From the Tedtalk website we read:<br />
<blockquote> Even the most worldly and well-traveled among us will have their perspectives shifted by Hans Rosling. A professor of global health at Sweden’s Karolinska Institute, his current work focuses on dispelling common myths about the so-called developing world, which (he points out) is no longer worlds away from the west. In fact, most of the third world is on the same trajectory toward health and prosperity, and many countries are moving twice as fast as the west did.<br><br><br />
<br />
What sets Rosling apart isn’t just his apt observations of broad social and economic trends, but the stunning way he presents them. Guaranteed: You’ve never seen data presented like this. in Rosling’s hands, data sings. Trends come to life. And the big picture — usually hazy at best — snaps into sharp focus. </blockquote><br />
We did indeed find his talk amazing<br><br />
<br />
You can listen to Peter Donnelly's talk [http://www.ted.com/talks/lang/eng/peter_donnelly_shows_how_stats_fool_juries.html here.]<br />
<br />
From the Ted Talk website we read: <br><br />
<br />
<blockquote><br />
Oxford mathematician Peter Donnelly reveals the common mistakes humans make in interpreting statistics -- and the devastating impact these errors can have on the outcome of criminal trials.<br><br />
</blockquote><br />
<br />
Peter begins with a couple of jokes which we did not find all that funny:<br><br />
<br />
<blockquote><br />
Statisticians are people who like figures but do not have the personality to become accountants<br><br><br />
<br />
How do you tell the introverted statistician from the extroverted statistician? The extroverted statistician is the one who looks at the other person's shoes.<br><br><br />
</blockquote><br />
<br />
Peter's approach is to provide a simple probability problem and then to show that the method used to solve this problem also applies to real life problems.<br><br />
<br />
His simple problem (which we shall see is not so simple) can be described as follows. If you toss a coin three times there are eight possible outcomes (patterns): HHH, HTT, HHT, HTH, TTT, TTH, THH, TTH. For our game Peter and Paul each choose one of these eight patters. Let's assume that Peter chooses HTT and Paul choose HTH. Then we toss a coin a sequence of times and the first player whose pattern occurs wins. Most people would say that the probability that Paul wins is 1/2 but alas that is not correct. There is a huge literature on finding the probability that Peter wins. See for example [http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html Introduction to Probability] by Grinstead and Snell pages 428-430.<br />
<br />
You can also see a nice nice discussion of this coin tossing problem by Martin Gardner, (1974) Mathematical games, Sci. Amer. 10, 120-125. Here you will find an elegant combinatorial solution to this coin tossing problem, due to John Conway. This article is also included in Gardner's book "Time Travel and Other Mathematical Bewilderments" and in some of his other books. <br />
<br />
Donnelly finishes his talk by discussing how this Penney's problem has been used in his field of research DNA and the role of DNA in the courts. He illustrates the problems of using DNA in the courts using the Sally Clark case, which we discussed in [http://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_11.01.html#item2 Chance News 11.01].<br />
<br />
Contributed by Laurie Snell<br />
<br />
==Fraud in Iranian election?==<br />
[http://www.washingtonpost.com/wp-dyn/content/article/2009/06/20/AR2009062000004.html The devil is in the digits ]<br><br />
Washington Post, 20 June 2009<br><br />
Bernd Beber and Alexandra Scacco<br />
<br />
Beber and Scacco are doctoral students in political science at Columbia University. In this article they argue that certain patterns in the reported electoral totals from this month's Iranian presidential elections give strong indications of tampering. Iran's Ministry of the Interior released data for 29 provinces, and the authors examined the reported vote totals for the four main candidates, Ahmadinejad, Mousavi, Karroubi and Mohsen Rezai. Among these 116 numbers, the authors focus on the last two digits, which they assert should be uniformly distributed. However, they report two statistical irregularities. First, regarding the final digits, they write<br />
<br />
<blockquote><br />
We find too many 7s and not enough 5s in the last digit. We expect each digit (0, 1, 2, and so on) to appear at the end of 10 percent of the vote counts. But in Iran's provincial results, the digit 7 appears 17 percent of the time, and only 4 percent of the results end in the number 5. Two such departures from the average -- a spike of 17 percent or more in one digit and a drop to 4 percent or less in another -- are extremely unlikely. Fewer than four in a hundred non-fraudulent elections would produce such numbers. <br />
</blockquote><br />
<br />
Next, they considered the last two digits together, and asked how many of the pairs contain non-adjacent digits (e.g., 32 has adjacent digits while 35 has non-adjacent digits). They report that only 62% of the pairs had non-adjacent digits, compared with the 70% that would be expected for random digits.<br />
<br />
Further investigations by Beber and Scacco, this time involving county level data (an average province in Iran contains about 12 counties), are discussed on [http://www.stat.columbia.edu/~cook/movabletype/archives/2009/06/combining_findi.html Andrew Gelman's blog]. At the county level, the last digits do not look suspicious, and the county results do add up to the reported province totals. Beber and Scacco speculate that if the province totals were indeed fabricated, as their earlier analysis suggests, then the county totals could have been made to match as follows: the first few digits of each county could be padded get the total to get in the right ballpark, and then fine adjustment on the last digits of just one county would be required to match the province figure. Indeed, they cite discussion of work by [http://www.good.is/post/so-was-there-actually-fraud-in-iran’s-election/ Walter Mebane] suggesting that the leading digits do look suspicious. Mebane has been regularly updating his analysis [http://www-personal.umich.edu/~wmebane/note24jun2009.pdf online]. <br />
<br />
A good collection of links related to this discussion from Pollster.com is available [http://www.pollster.com/blogs/roundup_analyses_of_fraud_in_i.php here]. <br />
<br />
Submitted by Bill Peterson, based on posts by Nancy Boynton and others to the Isolated Statisticians mailing list.<br><br />
<br />
==What’s good for the goose?==<br />
[http://www.usatoday.com/news/nation/2009-06-21-geese_N.htm#uslPageReturn “NYC Issues Geese Evictions”], by Martha T. Moore, USA Today, June 22, 2009<br><br />
<br />
The U.S. Department of Agriculture Wildlife Services has begun removing, for euthanization, about 2,000 geese from areas near New York City’s two airports, at a cost of about $100,000. In addition to the euthanization program, a Port Authority spokesperson stated that it was also “training airport employees to use a shotgun” as a “last resort.”<br><br />
<br />
This program is apparently a response to the January incident in which Canada geese “hit” US Airways Flight 1549, “shutting down the jet's engines and forcing the pilot to ditch in the Hudson River.” Not only were there no fatalities in this incident, but also, according to the NTSB, the geese were not local.<br><br />
<br />
According to FAA data, while the last airline fatality from a bird occurred in Boston in 1960, “the average annual number of large bird strikes has increased 62% since the 1990s.”<br><br />
<br />
Bloggers suggest that, at the very least, the geese could provide food for needy people.[http://content.usatoday.com/community/comments.aspx?id=35418290.story&=2#uslPageReturn]<br><br />
<br />
Discussion<br><br />
1. The last airline fatality from a bird occurred almost 50 years ago. If geese were only a problem with respect to airline safety, might this program be “overkill”? What information and/or data might you need in order to decide whether to support this program?<br><br />
2. The article tells us that the average annual number of large bird strikes at airplanes has increased by 62% since the 1990s. What additional information and/or data might you need in order to decide whether an increase of 62% is significant, statistically or otherwise? <br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Framing choices==<br />
[http://online.wsj.com/article/SB124545477468032915.html “About Time: Regulation Based On Human Nature”]<br><br />
by Jason Zweig, The Wall Street Journal, June 20, 2009<br><br />
In this column, Zweig writes about the need to provide consumers with clear, understandable options in choosing among complicated products such as mortgages.<br><br />
He refers to the 2009 revised edition of [http://nudges.org/index.cfm “Nudge: Improving Decisions About Health, Wealth, and Happiness”], by Richard Thaler (University of Chicago) and Cass Sunstein (Harvard Law School), who believe that financial institutions should be required to offer at least some “generic” mortgage plans that would make comparison-shopping easier.<br><br />
<blockquote>The central idea in “Nudge” is what Profs. Thaler and Sunstein call “choice architecture" – the context, format and framing of how decisions are presented to consumers. You will eat more nuts from a big bowl than from a small bowl. You will choose surgery if you are told it offers a 90% chance of survival; you will reject it if you are told there is a 10% chance it will kill you. The same people who would skip investing in a 401(k) if they had to "opt in" to the plan will participate if they have to "opt out" in order to skip it.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==More on Infuse and Kuklo II==<br />
<br />
Here is More on the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49#Infuse_and_Kuklo_ Infuse and Kuklo II story] that appeared in [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49 Chance News 49].<br />
<br />
From [http://74.125.95.132/search?q=cache:C1v8YN4CY1QJ:ryortho.com/NEWSSHORTS/volume5/issue19/06-19-09-NS-Medtronic.html+Machiavelli+advised+his+prince+to+get+all+the+bad+news+out+at+once+and+dribble+out+the+good+news.+It+would+be+good+advice+for+Medtronic+to+heed.&cd=1&hl=en&ct=clnk&gl=us&client=firefox-a]<br />
Orthopedics This Week we learn that "Medtronic has finally told Senator Charles Grassley how much it paid former Army surgeon Timothy Kuklo, M.D. Over $850,000 between 2001 and 2009." The article goes on to say, "Medtronic continues to dribble out details that raise more questions than answers." The article concludes with "Machiavelli advised his prince to get all the bad news out at once and dribble out the good news. It would be good advice for Medtronic to heed."<br />
<br />
Submitted by Paul Alper</div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_51&diff=8121Chance News 512009-07-08T13:41:10Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Passion is inversely proportional to the amount of real information available.</blockquote><div align=right>Gregory Benford, <i>Timescape</i>, 1980</div align=right><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
-----<br />
Re remark about the “attitudes and prejudices of the famous philosophers” in Chance News 49 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49], a 1924 Virginia sterilization law (not repealed until 1976) was upheld by the Supreme Court in <i>Buck v. Bell</i> in 1927, with Justice Oliver Wendell Holmes Jr. writing the majority opinion.<br><br />
<blockquote>“This woman [Carrie Bell] got railroaded. And one of the giants of the Supreme Court was driving the train.”</blockquote><br />
<div align=right>Paul Lombardo, quoted in "Terrible legacy of U.S. eugenics" [http://www.usatoday.com/news/health/2009-06-23-eugenics-carrie-buck_N.htm]<br><i>USA TODAY</i>, June 24, 2009</div align=right><br />
Submitted by Margaret Cibes<br><br />
-----<br />
<blockquote>Much of the fascination of statistics lies embedded in our gut feeling--and never trust a gut feeling--that abstract measures summarizing large tables of data must express something more real and fundamental than the data themselves. (Much professional training in statistics involves a conscious effort to counteract this gut feeling.) The technique of ''correlation'' has been particularly subject to such misuse because it seems to provide a path for inferences about causality (and indeed it does, sometimes--but only sometimes).</blockquote><br />
<br />
<div align=right>Page 269 in Stephen Jay Gould's <i>Mismeasure of Man</i>, 2nd edition </div align=right><br />
Submitted by Paul Alper<br />
<br />
==Forsooths==<br />
<br />
<blockquote>…. Let’s look at basketball …. The 1993 college basketball playoffs started with 64 teams. Of these, 15 were from schools with accredited library education programs.<br />
That’s an amazing statistic by itself, when you consider that there are only slightly more than three times that many library education programs in the United States, and that some of these don’t compete athletically in Division I. However, those 15 schools also went on to win 28 of the 63 games played, while losing only 14. The reason that there were only 14 losses is that the championship school has a library education program. So does the runnerup. Indeed, what sportswriters call the Final Four included three schools with accredited library education programs.<br><br />
…. Do I believe a single word of what I have just written? Of course not, although I have seen “research” studies … for which the hypotheses were no more credible.</blockquote><br />
<div align=right>Herbert S. White<br><br />
"Is There a Correlation Between Library Education Programs and Athletic Success?<br><i>Library Journal</i>, August 1993</div align=right><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
During <i>The Daily Show</i> on June 30, TV’s Jon Stewart gave out RIPPY (Rest-In-Peace) Awards [http://www.thedailyshow.com/video/index.jhtml?videoId=232234&title=The-Rippy-Awards-for-Outstanding-Achievement-in-Obitutainment&byDate=true] to television commentators for various aspects of their coverage of Michael Jackson’s death.<br />
<blockquote>It’s the award for attempts at mind-blowing analysis, and the winner is Extra’s Carlos Diaz [who stated on June 25]:<br><br />
People don’t realize the proximity of this whole thing. Farrah Fawcett passed away 5 hours, almost to the minute that Michael Jackson passed away 5 miles away. Ed McMahon passed away 48 hours previous [sic] at the same hospital that Michael Jackson passed away.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Credit utilization ratio==<br />
[http://www.time.com/time/magazine/article/0,9171,1904129,00.html “Is Your Credit Too Good? Why lenders are punishing those who borrow too little and always pay on time”]<br><br />
by Cybele Weisser, <i>TIME</i>, June 22, 2009<br><br />
<blockquote>[T]he formula for determining credit scores … looks at something called your “utilization ratio,” the total amount of credit you use vs. the amount you have available. If you have $25,000 worth of available credit and you put $5,000 on your cards every month, your utilization ratio is a healthy … 20%. But cut down that credit line to $10,000 and suddenly your ratio jumps to 50%, making you look pretty overextended.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Student-loan repayment for congressional staffers==<br />
[http://online.wsj.com/article/SB124578152192043001.html#articleTabs%3Dcomments “Scrutiny Grows as U.S. Pays Staffers’ Student Loans”]<br>by Elizabeth Williamson, <i>The Wall Street Journal</i>, June 25, 2009<br><br />
<br />
<blockquote>The House and Senate will spend $18 million this year repaying staffers' student loans. Last year, ... House lawmakers nearly doubled what the government can pay for their staffers' college bills. The yearly maximum repayment is $10,000 in fiscal 2009, which ends Sept. 30, up from $6,000 in fiscal 2008, with a lifetime maximum of $60,000, the same as in the executive branch. The House appropriated $13 million in 2009 for the program; as of last month, more than 2,200 House employees were getting the money.</blockquote><br />
<br />
<center>http://s.wsj.net/public/resources/images/NA-AY547_EXPENS_NS_20090624180410.gif</center><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Measuring excess risk==<br />
[http://www.usatoday.com/tech/science/environment/2009-06-23-epa-study_N.htm?loc=interstitialskip “EPA study: 2.2M live in areas where air poses cancer risk”]<br>by Brad Heath and Blake Morrison, <i>USA TODAY</i>, June 24, 2009<br><br />
<br />
This article gives a brief report about the National-Scale Air Toxics Assessment for 2002 [http://www.epa.gov/nata2002/factsheet.html], an EPA study of excess cancer risks from breathing 181 air toxics over an assumed lifetime of 70 years. The EPA updates information about air toxics emissions every three years, after which it conducts an analysis which is reviewed by the states, evaluated for accuracy, and released - apparently a long process.<br><br />
<br />
According to the EPA, the study found 2 million people with an increased cancer risk of greater than 100 in 1 million.<br><br />
<br />
According to the article, the study found air pollution to be a health threat “around major cities … although some of the counties where the air was even worse were in rural areas ….” The worst neighborhood was outside Los Angeles, where the estimated excess cancer risk was “more than 1,200 in 1 million, 34 times the national average.” The article provided no information about rural areas; however, the EPA provides a map [http://www.epa.gov/ttn/atw/nata2002/risksum.html] of most affected counties.<br />
<center>http://www.epa.gov/ttn/atw/nata2002/images/NATARisks100inaMil.jpg</center><br />
<br />
Discussion<br><br />
<br />
1. How might one measure <i>cancer risk</i>?<br><br />
<br />
2. What does it mean to measure <i>excess</i>, or <i>increased</i>, cancer risk?<br><br />
<br />
3. Why does the EPA measure excess risk over a <i>lifetime</i>? How do you think they identified people who had lived in a region over a lifetime? Would the fact that air pollution levels might change over a lifetime affect any aspect of the study?<br><br />
<br />
4. Estimate the national average excess cancer risk. Is it higher or lower than the EPA’s ceiling of 100 in 1 million? Do you think it makes sense to refer to a <i>national average</i> of excess cancer risk?<br><br />
<br />
5. Referring to the map, are you surprised about any of the locales with the highest excess cancer risk? If so, can you find any potential reason for high excess cancer risks in those locales?<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Too many cable TV channels?==<br />
[http://online.wsj.com/article/SB124603687047661927.html “Time to Screen Out Unloved Channels”]<br><br />
by Martin Peers, <i>The Wall Street Journal</i>, June 27, 2009<br><br />
(Full text may only be available to subscribers.)<br><br />
<br />
The author suggests that there are too many TV channels available and that this situation is driving subscriber costs up. He reports that "the average household tuned into only 16 channels of the 118 channels available.” He feels that charging fees in proportion to the sizes of viewing audiences would lower the cost of cable TV.<br><br />
He says that there is currently the “absence of correlation between the size of the fees paid to individual cable channels and their audiences.” Among non-premium channels, Nickelodeon was the most-watched cable channel in 2008, but its fees were not the highest (10th from the highest). Nickelodeon, with about 1.7 million daily household viewers, also had an annual affiliate revenue of about $300 per household, while Discovery Kids, with only 20,000 daily household viewers, had an annual affiliate revenue of about $1,900 per household.<br />
<center>http://s.wsj.net/public/resources/images/OB-DY540_TVHERD_NS_20090626193119.gif</center><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==True or false?==<br />
<blockquote>One hundred sleuthing statisticians running 100 different tests are about 100 times more likely than a lone investigator to find something fishy.</blockquote><br />
<div align=right>Carl Bialik, [http://online.wsj.com/article/SB124640788035376975.html "Rise and Flaw of Internet's Election-Fraud Hunters"]<br><br />
<i>The Wall Street Journal</i>, July 1, 2009</div align=right><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==New lottery study== <br />
[http://www.courant.com/news/connecticut/hc-poor-gamble-scratch-0703jul03c,0,7472516.column “Want False Hope With That Lottery Ticket?”]<br><br />
by Rick Green, <i>The Hartford Courant</i>, July 3, 2009<br><br />
<br />
A taxpayer-funded study by Spectrum Gaming Group [http://www.spectrumgaming.com/] is said to have found “no correlation between lottery sales and poverty.” The study claims that “because most successful lottery retailers were not located in higher poverty neighborhoods, there is no connection between income and ticket sales.”<br><br />
<br />
The Spectrum study contradicts many other studies, including one at Cornell University, where investigators “found ’a strong and positive relationship’ between lottery ticket sales and poverty rates after examining data from 39 states over 10 years.”<br><br />
<br />
The Spectrum study also contradicts a 2002 analysis done by the column’s author, Rick Green, and a colleague. They identified, by zip codes, the locales in which the highest concentrations of winners resided, not the locales in which the highest-selling retailers were located. Not surprisingly, these areas were in the poorest cities of Connecticut.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==30% chance for rain?==<br />
For many, meaning of rain forecast is cloudy at best.<br><br />
[http://www.usatoday.com/weather/research/2009-06-23-precipitation-forecast_N.htm <i>USA TODAY</i>], June 24, 2000<br><br />
Doyle Rice<br><br />
<br />
This news article begins with:<br><br />
<br />
<blockquote>When your local weather forecaster announces that there is a 30% chance of rain tomorrow, not everyone knows what that means. Some think it means 30% of an area will get rain. Others think it will rain for 30% of the day. In fact, of all the forecast terms used by meteorologists, this remains one of the most baffling to the public.<br><br><br />
<br />
Some people don't understand that the forecaster simply means there's a 30% probability it will rain at some point during the day. Susan Joslyn, a senior lecturer in the psychology department at the University of Washington in Seattle, and colleagues have been studying such confusion.</blockquote><br />
<br />
The news article explains the results of this study. There have been many studies like this. The following is a study which is often referred to when the "30% chance of rain problem" is brought up. <br />
<br />
Misinterpretations of Precipitation.<br><br />
Bulletin American Meteorological Society, Vol. 61, No 7, <br />
July 1980, p.695-701.<br><br />
Murphy, Licthenstein, Fischoff and Winkler<br><br />
<br />
We reviewed this article in [http://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_3.06.html#Misinterpretations Chance News 3.08] In this review we read:<br />
<br />
<blockquote>The authors wanted to see if there was a <br />
misunderstanding about the event being predicted, the <br />
meaning of probability or both. To test the <br />
understanding of the event, subjects were asked if the <br />
event being predicted was "rain somewhere in the <br />
region", "rain at a particular point in the region" <br />
"rain 20% of the time etc. Their answers led the authors <br />
to the conclusion that there is considerable <br />
misinterpretation on the meaning of the event. On the <br />
other hand, the subjects' answers to questions on the <br />
possible meaning of "20% chance" led them to conclude <br />
that the subjects did understand what the probability <br />
itself meant.<\blockquote><br />
<br />
I also talked to a couple of meteorologists who stated <br />
that it is unlikely that the public could understand <br />
what a 20% chance of rain means. Harold Brooks<br />
provided the following statement: <br><br />
<br />
<blockquote>According to the National Weather Service Operations Manual, <br />
The Probability of Precipitation (Pop) is <br />
The likelihood of occurrence (expressed as a percent) of a precipitation event <br />
at any given point in the forecast area. <br />
the time period to which the Pop applies <br />
must be clearly stated (or unambiguously <br />
inerferred from the forecast wording) since, <br />
without this, a numerical Pop value is <br />
meaningless. That is, it is the average point probability<br />
within the forecast area and the same PoP is<br />
assigned to each point. It can be shown that <br />
the PoP is equal to the expected area<br />
coverage of the precipitation (Schaefer, J. T. <br />
and R. L. Livingston, 1990: Operational <br />
implications of the "Probability of <br />
Precipitation". Weather. Forecasting, 5, <br />
354-356.).</blockquote><br />
<br />
This brings out fond memories. One of the earliest Chance Courses is described [http://www.dartmouth.edu/~chance/course/Syllabi/mpls/handouts/handouts.html here] where we read:<br />
<br />
This document consists of the collection of handouts for a two-week summer workshop entitled 'Geometry and the Imagination', being taught by Peter Doyle, Mark Foskey, Joan Garfield, Linda Green, and Laurie Snell at the Geometry Center in Minneapolis, 20 June-1 July, 1991. One of the documents includes the following homework:<br />
<br />
Read the materials on weather prediction.<br />
<br />
Problems<br />
<br />
(1) What do you make of all this?<br />
<br />
(2) What does Marilyn means when she says, `But rain doesn't obey the laws of chance; instead it obeys the laws of science.'<br />
<br />
(3) If the POP is 30% and it rains, was the forecaster correct?<br />
<br />
(4) Suppose that Minneapolis gets precipitation 3 days out of 10 over the long haul. Why not report a POP of 30% every single day?<br />
<br />
(5) San Diego county is spread out over a large area, comprising the coastal strip and inland valleys, the mountains, and the deserts. Separate forecasts are given for each region. Suppose, however, that the weather bureau computes a single POP for the whole area. On days on which this composite POP is 20%,<br />
what is the probability that a randomly selected resident of San Diego county will get rained on?<br />
<br />
(6) What do you think is the correct answer to the Reader reader's question?<br />
<br />
(7) There are contests to reward the best predictor of the weather. If you were running such a contest, how would you decide the winner?<br />
<br />
Readers might like to view two Chance video lectures about weather forecasting: (1) "How are Weather Predictions Determined by the National Weather Service?" [http://www.dartmouth.edu/~chance/ChanceLecture/Nweath/Nweath.htm], by Daniel Wilks, Cornell University; (2) "How are Local Weather Predictions Determined By Local Weather Forecasters?" [http://www.dartmouth.edu/~chance/ChanceLecture/Lweath/Lweath.htm], by Mark Breen, Fairbanks Museum.<br><br />
<br />
==Need for evidence==<br />
<br />
[http://www.time.com/time/politics/article/0,8599,1905340,00.html “How to Cut Health-Care Costs: Less Care, More Data”]<br><br />
by Michael Grunwald, <i>TIME</i>, June 29, 2009<br><br />
<br />
According to the author, President Obama has identified two major obstacles to more efficient health care delivery, the first of which is the current “fee-for-service” system in which hospitals and doctors are rewarded financially for ordering more tests and carrying out more procedures.<br />
<blockquote>The other big barrier is information: evidence-based medicine is hard to practice without evidence. …. So the things we know are dwarfed by the things we don’t know. …. [The] Mayo [Clinic] … has an institutional obsession with evidence-based medicine, using electronic records for in-house effectiveness research, constantly monitoring its doctors on everything from infection rates to operating times to patient outcomes, minimizing the art of medicine and maximizing the science. “We try to drive out variation wherever we can,” says Charles (Mike) Harper, a neurologist who oversees Mayo’s clinical practice in Rochester. “Practicing medicine is not the same as building Toyotas, but you can still standardize. Uncertainty shouldn’t be an excuse to ignore data.”</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Billions of almost-zeros==<br />
[http://www.newyorker.com/arts/critics/books/2009/07/06/090706crbo_books_gladwell “Priced to Sell”]<br><br />
by Malcolm Gladwell, <i>The New Yorker</i>, July 6 & 13, 2009<br><br />
<br />
In his new book, <i>Free: The Future of a Radical Price</i>, author Chris Anderson states:<br />
<blockquote>Distribution [of online videos] is now close enough to free to round down. Today, it costs about $0.25 to stream one hour of video to one person. Next year, it will be $0.15. A year later it will be less than a dime. Which is why YouTube’s founders decided to give it away.</blockquote><br />
In this book review, Malcolm Gladwell notes, however:<br />
<blockquote>Although the magic of Free technology means that the cost of serving up each video is “close enough to free to round down,” “close enough to free” multiplied by seventy-five billion is still a very large number.</blockquote><br />
<br />
A critique of Anderson's <i>Free</i>, and Ellen Ruppel's <i>Cheap</i>, can be found in <i>The New York Times</i>, July 5, 2009 [http://www.nytimes.com/2009/07/06/books/06maslin.html?_r=1&hpw].<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Love (food) and marriage?==<br />
[http://www.time.com/time/magazine/article/0,9171,1907143,00.html “First Comes Love, Then Comes Obesity?”]<br><br />
by Bonnie Rochman, <i>TIME</i>, July 6, 2009<br><br />
<br />
This article discusses a University of North Carolina study of the relationship between romance and obesity. Published in the July issue of <i>Obesity</i> , the study found that “married individuals are twice as likely to become obese as are people who are merely dating.” The study “tracked changes over a handful of years in the weight and relationship status of 6,949 individuals.” The effect of increased risk of obesity appears to have affected women more than men, for folks who lived together, whether married or not.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==When in the course of human events ...== <br />
[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Darticle “Two Centuries On, a Cryptologist Cracks a Presidential Code”]<br><br />
by Rachel Silverman, <i>The Wall Street Journal</i>, July 2, 2009<br><br />
<br />
The author reports that Lawren Smithline, a mathematician at the Center for Communications Research in Princeton, NJ, has deciphered a coded message in an 1801 letter to President Thomas Jefferson from a math professor at the University of Pennsylvania.<br><br />
<br />
The code [http://s.wsj.net/public/resources/documents/cipher0701.pdf], was not a “simple substitution cipher,” in which one letter of the alphabet is replaced with another, and so could not be cracked using ordinary frequency analysis. Nor was the code a “nomenclator,” which is a “catalog of numbers, each standing for a word, syllable, phrase or letter,” or a “wheel cipher,” which involves letters inscribed on the edge of a wheel that can be turned to scramble words.<br><br />
<br />
Mr. Patterson claimed “the utter impossibility of deciphering” his code, which involved a grid of the text, broken into sections. He estimated that a de-coder might have to try “upwards of ninety millions of millions” of potential combinations in order to solve his coded message to Jefferson.<br> <br />
<br />
Dr. Smithline analyzed Jefferson’s State of the Union addresses and counted the frequency of every possible pair of letters in the speeches. He used a “dynamic programming” algorithm to test some “educated guesses.” Fewer than 100,000 calculations were needed to solve the cipher.<br><br />
<br />
The following message emerged, a “little joke on Thomas Jefferson,” according to Dr. Smithline:<br />
<br />
<blockquote>In Congress, July Fourth, one thousand seven hundred and seventy six. A declaration by the Representatives of the United States of America in Congress assembled. When in the course of human events ....</blockquote><br />
"Patterson played this little joke on Thomas Jefferson," says Dr. Smithline. "And nobody knew until now."<br><br />
<br />
Two bloggers[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Dcomments] commented.<br><br />
<br />
(a) Ms. Silverman should have mentioned the fact that she picked up the story from the March-April 2009 edition of <i>American Scientist</i>, "A Cipher to Thomas Jefferson" [http://www.americanscientist.org/issues/feature/2009/2/a-cipher-to-thomas-jefferson].<br><br />
<br />
(b) If you'd like to read a fun story in which involves a replacement code, frequency analysis, and buried treasure, see Poe's short story, "The Gold-Bug" [http://www.eapoe.org/works/tales/goldbga2.htm].<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Joltin’ Joe==<br />
[http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#printMode “The Triumph of the Random”]<br><br />
by Leonard Mlodinow, <i>The Wall Street Journal</i>, July 3-5, 2009<br> <br />
<br />
This article discusses “streaks,” especially the 56 consecutive baseball games in which Joe DiMaggio had at least one hit, and people’s intuitions about them. The author [http://www.its.caltech.edu/~len/ ] is a Caltech professor, who wrote <i>The Drunkard’s Walk: How Randomness Rules Our Lives</i>.<br><br />
<br />
<blockquote>[R]andom processes do display periods of order. In a toss of 100 coins, for example, the chances are more than 75% that you will see a streak of six or more heads or tails, and almost 10% that you’ll produce a streak of 10 or more. As a result a streak can look quite impressive even if it is due to nothing more than chance. .... A few years ago Bill Miller of the Legg Mason Value Trust Fund was the most celebrated fund manager on Wall Street because his fund outperformed the broad market for 15 years straight. It was a feat compared regularly to DiMaggio’s, but if all the comparable fund managers over the past 40 years had been doing nothing but flipping coins, the chances are 75% that one of them would have matched or exceeded Mr. Miller’s streak.</blockquote><br />
The author argues that DiMaggio’s streak could have occurred by chance alone, based on DiMaggio’s lifetime batting average of 0.325, and the fact that hundreds of players had been trying for such a streak over a hundred years.<br><br />
<br />
The author points out that there are many factors involved in analyzing baseball streaks, <i>e.g.</i>, variations in batting averages over time. Samuel Arbesman and Stephen H. Strogatz, of Cornell, carried out a 10,000-case computer simulation based on baseball players’ actual statistics from each year 1871-2005. They found that streaks ranged from 39 games to 109 games, with 42% having streaks of DiMaggio’s length or longer.<br><br />
<br />
In discussing people’s misconceptions about streaks, the author cites Thomas Gilovich, Robert Vallone, and Amos Tversky’s paper, “The Hot Hand in Basketball: On the Misperception of Random Sequences.” [http://www.psych.cornell.edu/sec/pubPeople/tdg1/Gilo.Vallone.Tversky.pdf]<br><br />
<br />
Other resources not cited in this article include Thomas Gilovich’s 1998 Chance video lecture "Streaks in Sports" [http://www.dartmouth.edu/~chance/ChanceLecture/streak/streak.htm], and Stephen Jay Gould’s 1988 book review "The Streak of Streaks" [http://www.nybooks.com/articles/4337].<br><br />
<br />
Two bloggers [http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#articleTabs%3] commented:<br><br />
<br />
(a) Strogatz's simulation had Cobb out-hitting DiMaggio 300 out of 10000 times, or 3%. Dunno how long he played, but much longer than 3% of baseball. 10000 "seasons" is a sample 100 times greater than reality.<br><br />
<br />
(b) …. “Don’t give me brilliant generals; give me lucky generals.” –Caesar. …. As a former baseball player, I know how hard it is to get a hit on those days when you're just not feeling it. I don't think coins have those days.<br><br />
<br />
Discussion<br><br />
<br />
1. In a toss of 100 coins, what is the probability of seeing a streak of 6 or more <i>heads</i>? Here [http://www.bumblebeagle.org/horsehide/hitstreaks.html] is a website with an applet calculator and an explanation of the reasoning behind the calculations.<br><br />
<br />
2. Show that, in a toss of 100 coins, the probability of seeing a streak of 6 or more <i>heads or tails</i> is more than 75%.<br><br />
<br />
3. Comment on blogger (a)’s response to the article.<br><br />
<br />
Submitted by Margaret Cibes<br></div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_51&diff=8119Chance News 512009-07-08T00:09:41Z<p>PaulAlper: /* Quotations */</p>
<hr />
<div>==Quotations==<br />
<br />
<blockquote>Passion is inversely proportional to the amount of real information available.</blockquote><div align=right>Gregory Benford, <i>Timescape</i>, 1980</div align=right><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
-----<br />
Re remark about the “attitudes and prejudices of the famous philosophers” in Chance News 49 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49], a 1924 Virginia sterilization law (not repealed until 1976) was upheld by the Supreme Court in <i>Buck v. Bell</i> in 1927, with Justice Oliver Wendell Holmes Jr. writing the majority opinion.<br><br />
<blockquote>“This woman [Carrie Bell] got railroaded. And one of the giants of the Supreme Court was driving the train.”</blockquote><br />
<div align=right>Paul Lombardo, quoted in "Terrible legacy of U.S. eugenics" [http://www.usatoday.com/news/health/2009-06-23-eugenics-carrie-buck_N.htm]<br><i>USA TODAY</i>, June 24, 2009</div align=right><br />
Submitted by Margaret Cibes<br><br />
-----<br />
<blockquote>Much of the fascination of statistics lies embedded in our gut feeling--and never trust a gut feeling--that abstract measures summarizing large tables of data must express something more real and fundamental than the data themselves. (Much professional training in statistics involves a conscious effort to counteract this gut feeling.) The technique of correlation has been particularly subject to such misuse because it seems to provide a path for inferences about causality (and indeed it does, sometimes--but only sometimes).</blockquote><br />
<br />
<div align=right>Page 269 in Stephen Jay Gould's <i>Mismeasure of Man</i>, 2nd edition </div align=right><br />
Submitted by Paul Alper<br />
<br />
==Forsooths==<br />
<br />
<blockquote>…. Let’s look at basketball …. The 1993 college basketball playoffs started with 64 teams. Of these, 15 were from schools with accredited library education programs.<br />
That’s an amazing statistic by itself, when you consider that there are only slightly more than three times that many library education programs in the United States, and that some of these don’t compete athletically in Division I. However, those 15 schools also went on to win 28 of the 63 games played, while losing only 14. The reason that there were only 14 losses is that the championship school has a library education program. So does the runnerup. Indeed, what sportswriters call the Final Four included three schools with accredited library education programs.<br><br />
…. Do I believe a single word of what I have just written? Of course not, although I have seen “research” studies … for which the hypotheses were no more credible.</blockquote><br />
<div align=right>Herbert S. White<br><br />
"Is There a Correlation Between Library Education Programs and Athletic Success?<br><i>Library Journal</i>, August 1993</div align=right><br />
Submitted by Margaret Cibes<br><br />
<br />
<br />
During <i>The Daily Show</i> on June 30, TV’s Jon Stewart gave out RIPPY (Rest-In-Peace) Awards [http://www.thedailyshow.com/video/index.jhtml?videoId=232234&title=The-Rippy-Awards-for-Outstanding-Achievement-in-Obitutainment&byDate=true] to television commentators for various aspects of their coverage of Michael Jackson’s death.<br />
<blockquote>It’s the award for attempts at mind-blowing analysis, and the winner is Extra’s Carlos Diaz [who stated on June 25]:<br><br />
People don’t realize the proximity of this whole thing. Farrah Fawcett passed away 5 hours, almost to the minute that Michael Jackson passed away 5 miles away. Ed McMahon passed away 48 hours previous [sic] at the same hospital that Michael Jackson passed away.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Credit utilization ratio==<br />
[http://www.time.com/time/magazine/article/0,9171,1904129,00.html “Is Your Credit Too Good? Why lenders are punishing those who borrow too little and always pay on time”]<br><br />
by Cybele Weisser, <i>TIME</i>, June 22, 2009<br><br />
<blockquote>[T]he formula for determining credit scores … looks at something called your “utilization ratio,” the total amount of credit you use vs. the amount you have available. If you have $25,000 worth of available credit and you put $5,000 on your cards every month, your utilization ratio is a healthy … 20%. But cut down that credit line to $10,000 and suddenly your ratio jumps to 50%, making you look pretty overextended.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Student-loan repayment for congressional staffers==<br />
[http://online.wsj.com/article/SB124578152192043001.html#articleTabs%3Dcomments “Scrutiny Grows as U.S. Pays Staffers’ Student Loans”]<br>by Elizabeth Williamson, <i>The Wall Street Journal</i>, June 25, 2009<br><br />
<br />
<blockquote>The House and Senate will spend $18 million this year repaying staffers' student loans. Last year, ... House lawmakers nearly doubled what the government can pay for their staffers' college bills. The yearly maximum repayment is $10,000 in fiscal 2009, which ends Sept. 30, up from $6,000 in fiscal 2008, with a lifetime maximum of $60,000, the same as in the executive branch. The House appropriated $13 million in 2009 for the program; as of last month, more than 2,200 House employees were getting the money.</blockquote><br />
<br />
<center>http://s.wsj.net/public/resources/images/NA-AY547_EXPENS_NS_20090624180410.gif</center><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Measuring excess risk==<br />
[http://www.usatoday.com/tech/science/environment/2009-06-23-epa-study_N.htm?loc=interstitialskip “EPA study: 2.2M live in areas where air poses cancer risk”]<br>by Brad Heath and Blake Morrison, <i>USA TODAY</i>, June 24, 2009<br><br />
<br />
This article gives a brief report about the National-Scale Air Toxics Assessment for 2002 [http://www.epa.gov/nata2002/factsheet.html], an EPA study of excess cancer risks from breathing 181 air toxics over an assumed lifetime of 70 years. The EPA updates information about air toxics emissions every three years, after which it conducts an analysis which is reviewed by the states, evaluated for accuracy, and released - apparently a long process.<br><br />
<br />
According to the EPA, the study found 2 million people with an increased cancer risk of greater than 100 in 1 million.<br><br />
<br />
According to the article, the study found air pollution to be a health threat “around major cities … although some of the counties where the air was even worse were in rural areas ….” The worst neighborhood was outside Los Angeles, where the estimated excess cancer risk was “more than 1,200 in 1 million, 34 times the national average.” The article provided no information about rural areas; however, the EPA provides a map [http://www.epa.gov/ttn/atw/nata2002/risksum.html] of most affected counties.<br />
<center>http://www.epa.gov/ttn/atw/nata2002/images/NATARisks100inaMil.jpg</center><br />
<br />
Discussion<br><br />
<br />
1. How might one measure <i>cancer risk</i>?<br><br />
<br />
2. What does it mean to measure <i>excess</i>, or <i>increased</i>, cancer risk?<br><br />
<br />
3. Why does the EPA measure excess risk over a <i>lifetime</i>? How do you think they identified people who had lived in a region over a lifetime? Would the fact that air pollution levels might change over a lifetime affect any aspect of the study?<br><br />
<br />
4. Estimate the national average excess cancer risk. Is it higher or lower than the EPA’s ceiling of 100 in 1 million? Do you think it makes sense to refer to a <i>national average</i> of excess cancer risk?<br><br />
<br />
5. Referring to the map, are you surprised about any of the locales with the highest excess cancer risk? If so, can you find any potential reason for high excess cancer risks in those locales?<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Too many cable TV channels?==<br />
[http://online.wsj.com/article/SB124603687047661927.html “Time to Screen Out Unloved Channels”]<br><br />
by Martin Peers, <i>The Wall Street Journal</i>, June 27, 2009<br><br />
(Full text may only be available to subscribers.)<br><br />
<br />
The author suggests that there are too many TV channels available and that this situation is driving subscriber costs up. He reports that "the average household tuned into only 16 channels of the 118 channels available.” He feels that charging fees in proportion to the sizes of viewing audiences would lower the cost of cable TV.<br><br />
He says that there is currently the “absence of correlation between the size of the fees paid to individual cable channels and their audiences.” Among non-premium channels, Nickelodeon was the most-watched cable channel in 2008, but its fees were not the highest (10th from the highest). Nickelodeon, with about 1.7 million daily household viewers, also had an annual affiliate revenue of about $300 per household, while Discovery Kids, with only 20,000 daily household viewers, had an annual affiliate revenue of about $1,900 per household.<br />
<center>http://s.wsj.net/public/resources/images/OB-DY540_TVHERD_NS_20090626193119.gif</center><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==True or false?==<br />
<blockquote>One hundred sleuthing statisticians running 100 different tests are about 100 times more likely than a lone investigator to find something fishy.</blockquote><br />
<div align=right>Carl Bialik, [http://online.wsj.com/article/SB124640788035376975.html "Rise and Flaw of Internet's Election-Fraud Hunters"]<br><br />
<i>The Wall Street Journal</i>, July 1, 2009</div align=right><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==New lottery study== <br />
[http://www.courant.com/news/connecticut/hc-poor-gamble-scratch-0703jul03c,0,7472516.column “Want False Hope With That Lottery Ticket?”]<br><br />
by Rick Green, <i>The Hartford Courant</i>, July 3, 2009<br><br />
<br />
A taxpayer-funded study by Spectrum Gaming Group [http://www.spectrumgaming.com/] is said to have found “no correlation between lottery sales and poverty.” The study claims that “because most successful lottery retailers were not located in higher poverty neighborhoods, there is no connection between income and ticket sales.”<br><br />
<br />
The Spectrum study contradicts many other studies, including one at Cornell University, where investigators “found ’a strong and positive relationship’ between lottery ticket sales and poverty rates after examining data from 39 states over 10 years.”<br><br />
<br />
The Spectrum study also contradicts a 2002 analysis done by the column’s author, Rick Green, and a colleague. They identified, by zip codes, the locales in which the highest concentrations of winners resided, not the locales in which the highest-selling retailers were located. Not surprisingly, these areas were in the poorest cities of Connecticut.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==30% chance for rain?==<br />
For many, meaning of rain forecast is cloudy at best.<br><br />
[http://www.usatoday.com/weather/research/2009-06-23-precipitation-forecast_N.htm <i>USA TODAY</i>], June 24, 2000<br><br />
Doyle Rice<br><br />
<br />
This news article begins with:<br><br />
<br />
<blockquote>When your local weather forecaster announces that there is a 30% chance of rain tomorrow, not everyone knows what that means. Some think it means 30% of an area will get rain. Others think it will rain for 30% of the day. In fact, of all the forecast terms used by meteorologists, this remains one of the most baffling to the public.<br><br><br />
<br />
Some people don't understand that the forecaster simply means there's a 30% probability it will rain at some point during the day. Susan Joslyn, a senior lecturer in the psychology department at the University of Washington in Seattle, and colleagues have been studying such confusion.</blockquote><br />
<br />
The news article explains the results of this study. There have been many studies like this. The following is a study which is often referred to when the "30% chance of rain problem" is brought up. <br />
<br />
Misinterpretations of Precipitation.<br><br />
Bulletin American Meteorological Society, Vol. 61, No 7, <br />
July 1980, p.695-701.<br><br />
Murphy, Licthenstein, Fischoff and Winkler<br><br />
<br />
We reviewed this article in [http://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_3.06.html#Misinterpretations Chance News 3.08] In this review we read:<br />
<br />
<blockquote>The authors wanted to see if there was a <br />
misunderstanding about the event being predicted, the <br />
meaning of probability or both. To test the <br />
understanding of the event, subjects were asked if the <br />
event being predicted was "rain somewhere in the <br />
region", "rain at a particular point in the region" <br />
"rain 20% of the time etc. Their answers led the authors <br />
to the conclusion that there is considerable <br />
misinterpretation on the meaning of the event. On the <br />
other hand, the subjects' answers to questions on the <br />
possible meaning of "20% chance" led them to conclude <br />
that the subjects did understand what the probability <br />
itself meant.<\blockquote><br />
<br />
I also talked to a couple of meteorologists who stated <br />
that it is unlikely that the public could understand <br />
what a 20% chance of rain means. Harold Brooks<br />
provided the following statement: <br><br />
<br />
<blockquote>According to the National Weather Service Operations Manual, <br />
The Probability of Precipitation (Pop) is <br />
The likelihood of occurrence (expressed as a percent) of a precipitation event <br />
at any given point in the forecast area. <br />
the time period to which the Pop applies <br />
must be clearly stated (or unambiguously <br />
inerferred from the forecast wording) since, <br />
without this, a numerical Pop value is <br />
meaningless. That is, it is the average point probability<br />
within the forecast area and the same PoP is<br />
assigned to each point. It can be shown that <br />
the PoP is equal to the expected area<br />
coverage of the precipitation (Schaefer, J. T. <br />
and R. L. Livingston, 1990: Operational <br />
implications of the "Probability of <br />
Precipitation". Weather. Forecasting, 5, <br />
354-356.).</blockquote><br />
<br />
This brings out fond memories. One of the earliest Chance Courses is described [http://www.dartmouth.edu/~chance/course/Syllabi/mpls/handouts/handouts.html here] where we read:<br />
<br />
This document consists of the collection of handouts for a two-week summer workshop entitled 'Geometry and the Imagination', being taught by Peter Doyle, Mark Foskey, Joan Garfield, Linda Green, and Laurie Snell at the Geometry Center in Minneapolis, 20 June-1 July, 1991. One of the documents includes the following homework:<br />
<br />
Read the materials on weather prediction.<br />
<br />
Problems<br />
<br />
(1) What do you make of all this?<br />
<br />
(2) What does Marilyn means when she says, `But rain doesn't obey the laws of chance; instead it obeys the laws of science.'<br />
<br />
(3) If the POP is 30% and it rains, was the forecaster correct?<br />
<br />
(4) Suppose that Minneapolis gets precipitation 3 days out of 10 over the long haul. Why not report a POP of 30% every single day?<br />
<br />
(5) San Diego county is spread out over a large area, comprising the coastal strip and inland valleys, the mountains, and the deserts. Separate forecasts are given for each region. Suppose, however, that the weather bureau computes a single POP for the whole area. On days on which this composite POP is 20%,<br />
what is the probability that a randomly selected resident of San Diego county will get rained on?<br />
<br />
(6) What do you think is the correct answer to the Reader reader's question?<br />
<br />
(7) There are contests to reward the best predictor of the weather. If you were running such a contest, how would you decide the winner?<br />
<br />
Readers might like to view two Chance video lectures about weather forecasting: (1) "How are Weather Predictions Determined by the National Weather Service?" [http://www.dartmouth.edu/~chance/ChanceLecture/Nweath/Nweath.htm], by Daniel Wilks, Cornell University; (2) "How are Local Weather Predictions Determined By Local Weather Forecasters?" [http://www.dartmouth.edu/~chance/ChanceLecture/Lweath/Lweath.htm], by Mark Breen, Fairbanks Museum.<br><br />
<br />
==Need for evidence==<br />
<br />
[http://www.time.com/time/politics/article/0,8599,1905340,00.html “How to Cut Health-Care Costs: Less Care, More Data”]<br><br />
by Michael Grunwald, <i>TIME</i>, June 29, 2009<br><br />
<br />
According to the author, President Obama has identified two major obstacles to more efficient health care delivery, the first of which is the current “fee-for-service” system in which hospitals and doctors are rewarded financially for ordering more tests and carrying out more procedures.<br />
<blockquote>The other big barrier is information: evidence-based medicine is hard to practice without evidence. …. So the things we know are dwarfed by the things we don’t know. …. [The] Mayo [Clinic] … has an institutional obsession with evidence-based medicine, using electronic records for in-house effectiveness research, constantly monitoring its doctors on everything from infection rates to operating times to patient outcomes, minimizing the art of medicine and maximizing the science. “We try to drive out variation wherever we can,” says Charles (Mike) Harper, a neurologist who oversees Mayo’s clinical practice in Rochester. “Practicing medicine is not the same as building Toyotas, but you can still standardize. Uncertainty shouldn’t be an excuse to ignore data.”</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==Billions of almost-zeros==<br />
[http://www.newyorker.com/arts/critics/books/2009/07/06/090706crbo_books_gladwell “Priced to Sell”]<br><br />
by Malcolm Gladwell, <i>The New Yorker</i>, July 6 & 13, 2009<br><br />
<br />
In his new book, <i>Free: The Future of a Radical Price</i>, author Chris Anderson states:<br />
<blockquote>Distribution [of online videos] is now close enough to free to round down. Today, it costs about $0.25 to stream one hour of video to one person. Next year, it will be $0.15. A year later it will be less than a dime. Which is why YouTube’s founders decided to give it away.</blockquote><br />
In this book review, Malcolm Gladwell notes, however:<br />
<blockquote>Although the magic of Free technology means that the cost of serving up each video is “close enough to free to round down,” “close enough to free” multiplied by seventy-five billion is still a very large number.</blockquote><br />
<br />
A critique of Anderson's <i>Free</i>, and Ellen Ruppel's <i>Cheap</i>, can be found in <i>The New York Times</i>, July 5, 2009 [http://www.nytimes.com/2009/07/06/books/06maslin.html?_r=1&hpw].<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Love (food) and marriage?==<br />
[http://www.time.com/time/magazine/article/0,9171,1907143,00.html “First Comes Love, Then Comes Obesity?”]<br><br />
by Bonnie Rochman, <i>TIME</i>, July 6, 2009<br><br />
<br />
This article discusses a University of North Carolina study of the relationship between romance and obesity. Published in the July issue of <i>Obesity</i> , the study found that “married individuals are twice as likely to become obese as are people who are merely dating.” The study “tracked changes over a handful of years in the weight and relationship status of 6,949 individuals.” The effect of increased risk of obesity appears to have affected women more than men, for folks who lived together, whether married or not.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==When in the course of human events ...== <br />
[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Darticle “Two Centuries On, a Cryptologist Cracks a Presidential Code”]<br><br />
by Rachel Silverman, <i>The Wall Street Journal</i>, July 2, 2009<br><br />
<br />
The author reports that Lawren Smithline, a mathematician at the Center for Communications Research in Princeton, NJ, has deciphered a coded message in an 1801 letter to President Thomas Jefferson from a math professor at the University of Pennsylvania.<br><br />
<br />
The code [http://s.wsj.net/public/resources/documents/cipher0701.pdf], was not a “simple substitution cipher,” in which one letter of the alphabet is replaced with another, and so could not be cracked using ordinary frequency analysis. Nor was the code a “nomenclator,” which is a “catalog of numbers, each standing for a word, syllable, phrase or letter,” or a “wheel cipher,” which involves letters inscribed on the edge of a wheel that can be turned to scramble words.<br><br />
<br />
Mr. Patterson claimed “the utter impossibility of deciphering” his code, which involved a grid of the text, broken into sections. He estimated that a de-coder might have to try “upwards of ninety millions of millions” of potential combinations in order to solve his coded message to Jefferson.<br> <br />
<br />
Dr. Smithline analyzed Jefferson’s State of the Union addresses and counted the frequency of every possible pair of letters in the speeches. He used a “dynamic programming” algorithm to test some “educated guesses.” Fewer than 100,000 calculations were needed to solve the cipher.<br><br />
<br />
The following message emerged, a “little joke on Thomas Jefferson,” according to Dr. Smithline:<br />
<br />
<blockquote>In Congress, July Fourth, one thousand seven hundred and seventy six. A declaration by the Representatives of the United States of America in Congress assembled. When in the course of human events ....</blockquote><br />
"Patterson played this little joke on Thomas Jefferson," says Dr. Smithline. "And nobody knew until now."<br><br />
<br />
Two bloggers[http://online.wsj.com/article/SB124648494429082661.html#articleTabs%3Dcomments] commented.<br><br />
<br />
(a) Ms. Silverman should have mentioned the fact that she picked up the story from the March-April 2009 edition of <i>American Scientist</i>, "A Cipher to Thomas Jefferson" [http://www.americanscientist.org/issues/feature/2009/2/a-cipher-to-thomas-jefferson].<br><br />
<br />
(b) If you'd like to read a fun story in which involves a replacement code, frequency analysis, and buried treasure, see Poe's short story, "The Gold-Bug" [http://www.eapoe.org/works/tales/goldbga2.htm].<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Joltin’ Joe==<br />
[http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#printMode “The Triumph of the Random”]<br><br />
by Leonard Mlodinow, <i>The Wall Street Journal</i>, July 3-5, 2009<br> <br />
<br />
This article discusses “streaks,” especially the 56 consecutive baseball games in which Joe DiMaggio had at least one hit, and people’s intuitions about them. The author [http://www.its.caltech.edu/~len/ ] is a Caltech professor, who wrote <i>The Drunkard’s Walk: How Randomness Rules Our Lives</i>.<br><br />
<br />
<blockquote>[R]andom processes do display periods of order. In a toss of 100 coins, for example, the chances are more than 75% that you will see a streak of six or more heads or tails, and almost 10% that you’ll produce a streak of 10 or more. As a result a streak can look quite impressive even if it is due to nothing more than chance. .... A few years ago Bill Miller of the Legg Mason Value Trust Fund was the most celebrated fund manager on Wall Street because his fund outperformed the broad market for 15 years straight. It was a feat compared regularly to DiMaggio’s, but if all the comparable fund managers over the past 40 years had been doing nothing but flipping coins, the chances are 75% that one of them would have matched or exceeded Mr. Miller’s streak.</blockquote><br />
The author argues that DiMaggio’s streak could have occurred by chance alone, based on DiMaggio’s lifetime batting average of 0.325, and the fact that hundreds of players had been trying for such a streak over a hundred years.<br><br />
<br />
The author points out that there are many factors involved in analyzing baseball streaks, <i>e.g.</i>, variations in batting averages over time. Samuel Arbesman and Stephen H. Strogatz, of Cornell, carried out a 10,000-case computer simulation based on baseball players’ actual statistics from each year 1871-2005. They found that streaks ranged from 39 games to 109 games, with 42% having streaks of DiMaggio’s length or longer.<br><br />
<br />
In discussing people’s misconceptions about streaks, the author cites Thomas Gilovich, Robert Vallone, and Amos Tversky’s paper, “The Hot Hand in Basketball: On the Misperception of Random Sequences.” [http://www.psych.cornell.edu/sec/pubPeople/tdg1/Gilo.Vallone.Tversky.pdf]<br><br />
<br />
Other resources not cited in this article include Thomas Gilovich’s 1998 Chance video lecture "Streaks in Sports" [http://www.dartmouth.edu/~chance/ChanceLecture/streak/streak.htm], and Stephen Jay Gould’s 1988 book review "The Streak of Streaks" [http://www.nybooks.com/articles/4337].<br><br />
<br />
Two bloggers [http://online.wsj.com/article/SB10001424052970204556804574261942466979118.html#articleTabs%3] commented:<br><br />
<br />
(a) Strogatz's simulation had Cobb out-hitting DiMaggio 300 out of 10000 times, or 3%. Dunno how long he played, but much longer than 3% of baseball. 10000 "seasons" is a sample 100 times greater than reality.<br><br />
<br />
(b) …. “Don’t give me brilliant generals; give me lucky generals.” –Caesar. …. As a former baseball player, I know how hard it is to get a hit on those days when you're just not feeling it. I don't think coins have those days.<br><br />
<br />
Discussion<br><br />
<br />
1. In a toss of 100 coins, what is the probability of seeing a streak of 6 or more <i>heads</i>? Here [http://www.bumblebeagle.org/horsehide/hitstreaks.html] is a website with an applet calculator and an explanation of the reasoning behind the calculations.<br><br />
<br />
2. Show that, in a toss of 100 coins, the probability of seeing a streak of 6 or more <i>heads or tails</i> is more than 75%.<br><br />
<br />
3. Comment on blogger (a)’s response to the article.<br><br />
<br />
Submitted by Margaret Cibes<br></div>PaulAlperhttps://www.causeweb.org/wiki/chance/index.php?title=Chance_News_50&diff=8120Chance News 502009-07-07T18:13:15Z<p>PaulAlper: /* Forsooths */</p>
<hr />
<div>==Quotation==<br />
<br />
<blockquote><br />
Probability is a mathematical discipline whose aims are akins to those, for example, of geometry of analytical mechanics. In each field we must carefully distinguish three aspects of the theory: (a) the formal logical content, (b) the intuitive background, and (c) the applications. The character, and the charm, of the whole structure cannot be appreciated without considering all three aspects in their proper relation.</blockquote><br />
<br />
<div align=right> William Feller<br><br />
An Introduction to Probability Theory and its Applications<br />
</div align=right><br><br />
<br />
This quotation was found at the [http://www.mathcs.carleton.edu/probweb/ Probability Web] which our readers will enjoy.<br />
<br />
==Forsooths==<br />
<br />
Naomi Schaefer Riley writes in the Wall Street Journal of 6/23/09 regarding a Colorado appeals court ruling which declared that "the public interest is advanced more by tenure systems that favor academic freedom over tenure systems that favor flexibility in hiring or firing." She then offers this statement, "Some of the courses taught this year by the professors who sued include American Baseball History and Business Statistics."<br />
<br />
<br />
Paul Alper<br />
-----<br />
This graphic has counter-intuitive coloring.<br />
http://graphics8.nytimes.com/images/2009/06/27/opinion/27blowlarge.jpg<br />
<br />
The accompanying article is<br />
[http://www.nytimes.com/2009/06/27/opinion/27blow.htm here]<br />
<br />
Paul Alper<br />
<br />
==Swine flu pandemonium III==<br />
<br />
[http://www.courant.com/news/custom/topnews/hc-swine-flu-death-0619.artjun19,0,5392611.story "Fourth Connecticut Resident With Swine Flu Dies"] by Arielle Levin Becker, The Hartford Courant, June 19, 2009<br><br />
See Chance News 49 [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49] for two earlier stories about the second and third cases of swine flu in Connecticut.<br><br />
<br />
A fourth Connecticut death has been "linked" to swine flu. <br />
<blockquote>The person was between 40 and 49 years old and had underlying medical conditions that increased the risk for serious illness from flu, the state Department of Public health said.</blockquote><br />
<br />
To date there have been 767 confirmed cases of swine flu, 28 of the cases had been hospitalized, and 19 of the hospitalized were from the largest cities. All four deaths occurred in people with other medical problems who were hospitalized at the time of death.<br><br />
<br />
Here is the data to date about Connecticut deaths from swine flu:<br><br />
1 death – 395 confirmed cases – June 4<br><br />
2 deaths – 637 confirmed cases – June 11<br><br />
3 deaths – 693 confirmed cases – June 15<br><br />
4 deaths – 767 confirmed cases – June 17<br><br />
<br />
Discussion<br><br />
<br />
1. Would you advise Connecticut residents to move out of large cities to avoid swine flu? Could the victims have been identified as being from the largest cities because they died in large city hospitals, as opposed to having resided in large cities?<br><br />
2. Would you advise Connecticut residents with swine flu to avoid hospitals?<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Swine flu pandemonium IV==<br />
[http://online.wsj.com/article/SB20001424052970204038304574149682916937774.html “Fever, Chills…and Losses: More Companies Should Be Preparing for an Influenza Pandemic”]<br><br />
by Amin Mawani, The Wall Street Journal, June 22, 2009<br><br />
Employers are urged to prepare for a possibly sizeable increase in employee absenteeism from swine flu, the first pandemic declared by the World Health Organization in 41 years. The World Economic Forum predicts a $500 billion economic impact from the pandemic.<br><br />
<blockquote>The good news is that employee absenteeism—and its financial toll on employers—may be controlled to a large extent with adequate planning and stockpiling of antiviral medication, masks and gowns.</blockquote><br />
<blockquote>The bad news is that few companies have taken steps to protect themselves. A 2007 survey reported at a Harvard Business School conference on pandemic planning found that while 88% of companies seemed prepared to deal with a power disruption and 70% with a technological failure, only 13% were prepared for the kind of labor-force disruption that would come with a pandemic.</blockquote><br />
Companies are advised to use cost-benefit analysis to justify preparedness. A company’s benefits associated with “pandemic preparedness” include “the earnings before interest, taxes, depreciation and amortization … that are preserved because employees aren’t absent. To figure this, managers must establish the contribution employees make to profits. Some of these calculations can get complex ….” A company that is prepared may also have a competitive edge due to reliability in bad times, as well as a reduced likelihood of being liable for negligence in governance.<br><br />
Submitted by Margaret Cibes<br><br />
<br />
==Role of luck in golf==<br />
<br />
[http://online.wsj.com/article/SB10001424052970204119704574236053876659482.html "Winning a Major May Just Be a Matter of Luck"], by Jason Turbow, The Wall Street Journal, June 19, 2009<br><br />
<br />
Using data from every PGA leadership board from 1998 to 2001, two business professors, from University of North Carolina and Dartmouth, have used "cubic spline functions" to try to explain the role of luck in professional golf.<br> <br />
<br />
<blockquote>"If being on the leaderboard at the end of a tournament was due entirely to skill, we would see the same names every week," said [the Dartmouth researcher]."</blockquote><br />
<br />
Their model aims to predict an individual's score in a tournament based on an estimate of the person's "intrinsic skill level independent of variables like course difficulty and variations over time." A golfer with a higher tournament score than predicted was considered to have had good luck; one with a lower score was considered to have had bad luck.<br><br />
<br />
<blockquote>[I]n all the events the researchers studied, Mr. Woods was the only golfer to win a tournament despite suffering from negative luck.</blockquote><br />
<br />
The brief article includes a table [http://online.wsj.com/article/SB10001424052970204119704574236053876659482.html] of expected score, actual score, and "luck factor" for players Tiger Woods, Ernie Els, Vijay Singh, Phil Mickelson, Sergio Garcia, and Jim Furyk, in the 2000 U.S. Open.<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Baseball: More education, more victories?==<br />
[http://online.wsj.com/article/SB124511558996917441.html "Who Has the Brainiest Team in Baseball?"], by Jason Turbow, The Wall Street Journal, June 16, 2009<br><br />
<br />
The author studied "30 team media guides" to try to determine whether there is "a correlation between education and victories" in professional baseball. He compared team standings with players' and managers' undergraduate degrees. He found that only about two dozen major league players or managers had undergraduate degrees.<br> <br />
<br />
<blockquote>[T]hree "All-Brains" division leaders -- Oakland, Arizona and Washington -- are in last place in real life, while Texas and the Dodgers were last in their divisions in smarts but first in the standings.</blockquote><br />
<br />
Two bloggers [http://online.wsj.com/article/SB124511558996917441.html#articleTabs%3Dcomments] wrote:<br><br />
<br />
(1) "[A]re these results really surprising? The best teams are the best teams because they have more good players than the other teams. Good players are likely to have been A) so talented at baseball as to have little incentive to work hard at school and B) so dedicated to the sport that academics would have suffered. If you're a marginal major league talent like Breslow, it makes sense to get a degree with better earnings potential. Not so for the Alex Rodriguezes [sic] and Barry Bondses [sic] of the world."<br><br />
<br />
(2) "How about instead of looking at university experience, check out something that almost every player (from the U.S., at least) would have: SAT scores. Surely there is the occasional ballplayer with a stratospheric score who still opts for baseball over college."<br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Keeping up with the Joneses by lowering utility bills==<br />
[http://www.theatlantic.com/doc/200907/green-envy “Greening With Envy”], by Bonnie Tsui, The Atlantic, August 2009<br><br />
Robert Cialdini, a social psychologist at Arizona State University, tested 4 different hotel reuse-towels signs to test how well guests responded:<br />
<blockquote>The first sign had the traditional message, asking guests to “do it for the environment.” The second asked guests to “cooperate with the hotel” and “be our partner in this cause” (12 percent less effective than the first). The third stated that the majority of guests in the hotel reused towels at least once during their stay (18 percent more effective). The last message was even more specific: it said that the majority of guests “in this room” had reused their towels. It produced a 33 percent increase in response behavior over the traditional message.</blockquote><br />
As the chief scientist for Positive Energy, Cialdini is now applying what he learned to encouraging utility consumers to conserve energy by letting them know how much energy they use relative to their neighbors. Based on his software’s analysis of a neighborhood’s energy usage, a utility company can send monthly bills to consumers with information about how a particular consumer’s usage compared to that of his/her neighbors. For example, a consumer who used “58 percent less electricity” might receive a row of smiley faces, while one who used “39 percent more” might receive no smiley faces, a notice that it cost him/her $741 extra, and tips for improvement.<br><br />
In Sacramento, <br />
<blockquote>people who received personalized “compared with your neighbors” data on their statements reduced their energy use by more than 2 percent over the course of a year. … [W]ith the pilot sample of 35,000 homes, it’s the equivalent of taking 700 homes off the grid. And the cost to the utility is minor: for every dollar a utility spends on a solar power plant, it produces 3 to 4 kilowatt-hours; for every dollar a utility spends on the energy reports, it saves 10 times that.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==A Probability puzzle==<br />
<br />
The [http://www.msri.org/ Mathematical Science Research Institute] has a monthly newsletter called [http://www.msri.org/communications/emissary/index_html The Emissary].This newsletter has, among other things, puzzles. For the Spring 2009 issue, Puzzle 5 was:<br />
<blockquote><br />
Find three random variables X, Y, Z, each uniformly distributed<br />
on [0, 1], such that their sum is constant. (Since each random variable<br />
has expectation 1 the sum must in fact be 3.)<br />
</blockquote><br />
<br />
To better understand this puzzle, consider the case of two random variables X and Y with X a random choice on 0 to 1 and Y = 1- X. Then the sum of X and Y is the constant 1. <br />
<br />
Comment: This puzzle is due to Thomas Colhurst<br />
<br />
Submitted by Laurie Snell<br />
<br />
==The Ted Talks==<br />
<br />
At the Ted talks [http://www.ted.com/pages/view/id/47 website] we read:<br />
<br />
<blockquote> Each year, the world's leading thinkers and doers gather in for an event many describe as the highlight of their year. Attendees have called it "The ultimate brain spa," "Davos for optimists" and "A four-day journey into the future, in the company of those creating it." This event is called TED, and it's truly a conference like no other.<br><BR><br />
"It was incredible." Malcolm Gladwell <br><br />
"A mind-opening experience." Amy Tan <br><br />
"One of the highlights of my entire life." Billy Graham <br><br />
"I've never experienced anything remotely like it." Jeffrey Katzenberg <br><br />
"The combined IQ of the attendees is incredible." Bill Gates </blockquote><br />
<br />
Of course we are interested in statistics or probability talks. We found two statistics talks, one by Hans Rosling and another by Peter Donnelly. You can listen to Rosling's talk [http://www.ted.com/talks/lang/eng/hans_rosling_shows_the_best_stats_you_ve_ever_seen.html here.]<br />
<br />
From the Tedtalk website we read:<br />
<blockquote> Even the most worldly and well-traveled among us will have their perspectives shifted by Hans Rosling. A professor of global health at Sweden’s Karolinska Institute, his current work focuses on dispelling common myths about the so-called developing world, which (he points out) is no longer worlds away from the west. In fact, most of the third world is on the same trajectory toward health and prosperity, and many countries are moving twice as fast as the west did.<br><br><br />
<br />
What sets Rosling apart isn’t just his apt observations of broad social and economic trends, but the stunning way he presents them. Guaranteed: You’ve never seen data presented like this. in Rosling’s hands, data sings. Trends come to life. And the big picture — usually hazy at best — snaps into sharp focus. </blockquote><br />
We did indeed find his talk amazing<br><br />
<br />
You can listen to Peter Donnelly's talk [http://www.ted.com/talks/lang/eng/peter_donnelly_shows_how_stats_fool_juries.html here.]<br />
<br />
From the Ted Talk website we read: <br><br />
<br />
<blockquote><br />
Oxford mathematician Peter Donnelly reveals the common mistakes humans make in interpreting statistics -- and the devastating impact these errors can have on the outcome of criminal trials.<br><br />
</blockquote><br />
<br />
Peter begins with a couple of jokes which we did not find all that funny:<br><br />
<br />
<blockquote><br />
Statisticians are people who like figures but do not have the personality to become accountants<br><br><br />
<br />
How do you tell the introverted statistician from the extroverted statistician? The extroverted statistician is the one who looks at the other person's shoes.<br><br><br />
</blockquote><br />
<br />
Peter's approach is to provide a simple probability problem and then to show that the method used to solve this problem also applies to real life problems.<br><br />
<br />
His simple problem (which we shall see is not so simple) can be described as follows. If you toss a coin three times there are eight possible outcomes (patterns): HHH, HTT, HHT, HTH, TTT, TTH, THH, TTH. For our game Peter and Paul each choose one of these eight patters. Let's assume that Peter chooses HTT and Paul choose HTH. Then we toss a coin a sequence of times and the first player whose pattern occurs wins. Most people would say that the probability that Paul win is 1/2 but alas that is not correct. There is a huge literature on finding the probability that Peter wins. See for example [http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html Introduction to Probability] by Grinstead and Snell pages 428-430.<br />
<br />
You can also see a nice nice discussion of this coin tossing problem by Martin Gardner, (1974) Mathematical games, Sci. Amer. 10, 120-125. Here you will find an elegant combinatorial solution to this coin tossing problem, due to John Conway. This article is also included in Gardner's book "Time Travel and Other Mathematical Bewilderments" and in some of his other books. <br />
<br />
Donnelly finishes his talk by discussing how this Penney's problem has been used in his field of research DNA and the role of DNA in the courts. He illustrates the problems of using DNA in the courts using the Sally Clark case, which we discussed in [http://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_11.01.html#item2 Chance News 11.01].<br />
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Contributed by Laurie Snell<br />
<br />
==Fraud in Iranian election?==<br />
[http://www.washingtonpost.com/wp-dyn/content/article/2009/06/20/AR2009062000004.html The devil is in the digits ]<br><br />
Washington Post, 20 June 2009<br><br />
Bernd Beber and Alexandra Scacco<br />
<br />
Beber and Scacco are doctoral students in political science at Columbia University. In this article they argue that certain patterns in the reported electoral totals from this month's Iranian presidential elections give strong indications of tampering. Iran's Ministry of the Interior released data for 29 provinces, and the authors examined the reported vote totals for the four main candidates, Ahmadinejad, Mousavi, Karroubi and Mohsen Rezai. Among these 116 numbers, the authors focus on the last two digits, which they assert should be uniformly distributed. However, they report two statistical irregularities. First, regarding the final digits, they write<br />
<br />
<blockquote><br />
We find too many 7s and not enough 5s in the last digit. We expect each digit (0, 1, 2, and so on) to appear at the end of 10 percent of the vote counts. But in Iran's provincial results, the digit 7 appears 17 percent of the time, and only 4 percent of the results end in the number 5. Two such departures from the average -- a spike of 17 percent or more in one digit and a drop to 4 percent or less in another -- are extremely unlikely. Fewer than four in a hundred non-fraudulent elections would produce such numbers. <br />
</blockquote><br />
<br />
Next, they considered the last two digits together, and asked how many of the pairs contain non-adjacent digits (e.g., 32 has adjacent digits while 35 has non-adjacent digits). They report that only 62% of the pairs had non-adjacent digits, compared with the 70% that would be expected for random digits.<br />
<br />
Further investigations by Beber and Scacco, this time involving county level data (an average province in Iran contains about 12 counties), are discussed on [http://www.stat.columbia.edu/~cook/movabletype/archives/2009/06/combining_findi.html Andrew Gelman's blog]. At the county level, the last digits do not look suspicious, and the county results do add up to the reported province totals. Beber and Scacco speculate that if the province totals were indeed fabricated, as their earlier analysis suggests, then the county totals could have been made to match as follows: the first few digits of each county could be padded get the total to get in the right ballpark, and then fine adjustment on the last digits of just one county would be required to match the province figure. Indeed, they cite discussion of work by [http://www.good.is/post/so-was-there-actually-fraud-in-iran’s-election/ Walter Mebane] suggesting that the leading digits do look suspicious. Mebane has been regularly updating his analysis [http://www-personal.umich.edu/~wmebane/note24jun2009.pdf online]. <br />
<br />
A good collection of links related to this discussion from Pollster.com is available [http://www.pollster.com/blogs/roundup_analyses_of_fraud_in_i.php here]. <br />
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Submitted by Bill Peterson, based on posts by Nancy Boynton and others to the Isolated Statisticians mailing list.<br><br />
<br />
==What’s good for the goose?==<br />
[http://www.usatoday.com/news/nation/2009-06-21-geese_N.htm#uslPageReturn “NYC Issues Geese Evictions”], by Martha T. Moore, USA Today, June 22, 2009<br><br />
<br />
The U.S. Department of Agriculture Wildlife Services has begun removing, for euthanization, about 2,000 geese from areas near New York City’s two airports, at a cost of about $100,000. In addition to the euthanization program, a Port Authority spokesperson stated that it was also “training airport employees to use a shotgun” as a “last resort.”<br><br />
<br />
This program is apparently a response to the January incident in which Canada geese “hit” US Airways Flight 1549, “shutting down the jet's engines and forcing the pilot to ditch in the Hudson River.” Not only were there no fatalities in this incident, but also, according to the NTSB, the geese were not local.<br><br />
<br />
According to FAA data, while the last airline fatality from a bird occurred in Boston in 1960, “the average annual number of large bird strikes has increased 62% since the 1990s.”<br><br />
<br />
Bloggers suggest that, at the very least, the geese could provide food for needy people.[http://content.usatoday.com/community/comments.aspx?id=35418290.story&=2#uslPageReturn]<br><br />
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Discussion<br><br />
1. The last airline fatality from a bird occurred almost 50 years ago. If geese were only a problem with respect to airline safety, might this program be “overkill”? What information and/or data might you need in order to decide whether to support this program?<br><br />
2. The article tells us that the average annual number of large bird strikes at airplanes has increased by 62% since the 1990s. What additional information and/or data might you need in order to decide whether an increase of 62% is significant, statistically or otherwise? <br><br />
<br />
Submitted by Margaret Cibes<br><br />
<br />
==Framing choices==<br />
[http://online.wsj.com/article/SB124545477468032915.html “About Time: Regulation Based On Human Nature”]<br><br />
by Jason Zweig, The Wall Street Journal, June 20, 2009<br><br />
In this column, Zweig writes about the need to provide consumers with clear, understandable options in choosing among complicated products such as mortgages.<br><br />
He refers to the 2009 revised edition of [http://nudges.org/index.cfm “Nudge: Improving Decisions About Health, Wealth, and Happiness”], by Richard Thaler (University of Chicago) and Cass Sunstein (Harvard Law School), who believe that financial institutions should be required to offer at least some “generic” mortgage plans that would make comparison-shopping easier.<br><br />
<blockquote>The central idea in “Nudge” is what Profs. Thaler and Sunstein call “choice architecture" – the context, format and framing of how decisions are presented to consumers. You will eat more nuts from a big bowl than from a small bowl. You will choose surgery if you are told it offers a 90% chance of survival; you will reject it if you are told there is a 10% chance it will kill you. The same people who would skip investing in a 401(k) if they had to "opt in" to the plan will participate if they have to "opt out" in order to skip it.</blockquote><br />
Submitted by Margaret Cibes<br><br />
<br />
==More on Infuse and Kuklo II==<br />
<br />
Here is More on the [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49#Infuse_and_Kuklo_ Infuse and Kuklo II story] that appeared in [http://chance.dartmouth.edu/chancewiki/index.php/Chance_News_49 Chance News 49].<br />
<br />
From [http://74.125.95.132/search?q=cache:C1v8YN4CY1QJ:ryortho.com/NEWSSHORTS/volume5/issue19/06-19-09-NS-Medtronic.html+Machiavelli+advised+his+prince+to+get+all+the+bad+news+out+at+once+and+dribble+out+the+good+news.+It+would+be+good+advice+for+Medtronic+to+heed.&cd=1&hl=en&ct=clnk&gl=us&client=firefox-a]<br />
Orthopedics This Week we learn that "Medtronic has finally told Senator Charles Grassley how much it paid former Army surgeon Timothy Kuklo, M.D. Over $850,000 between 2001 and 2009." The article goes on to say, "Medtronic continues to dribble out details that raise more questions than answers." The article concludes with "Machiavelli advised his prince to get all the bad news out at once and dribble out the good news. It would be good advice for Medtronic to heed."<br />
<br />
Submitted by Paul Alper</div>PaulAlper