Difference between revisions of "Sandbox"

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==False Memories==
 
  
Particularly in this age of Google, Wikipedia, YouTube, and the internet, you can’t believe everything you read, hear or see.  Moreover, according to [http://www.guardian.co.uk/commentisfree/2009/apr/04/ben-goldacre-auschwitz-bad-science Ben Goldacre] even memory can be dramatically wrong.  Goldacre refers to an article by [http://d.scribd.com/docs/uxdkbkuu7mol1e4gmm3.pdf de Vito, et al] and should be read in its entirety.
 
"On an abstract level, there's a good short report in the journal Cortex, where researchers in Bologna demonstrate the spectacular hopelessness of memory. One morning in 1980 a bomb exploded in Bologna station: 85 people died, and the clock stopped ominously showing 10.25, the time of the explosion. This image became a famous symbol for the event, but the clock was repaired soon after and worked perfectly for the next 16 years. When it broke again in 1996, it was decided to leave the clock showing 10.25 permanently, as a memorial."
 
  
http://www.dartmouth.edu/~chance/forwiki/Bologna.gif
+
==Forsooth==
  
The clock at the Bolgna railroad station stopped at<br>
+
==Quotations==
10.25 to mark the time of the terroristic massacre
+
“We know that people tend to overestimate the frequency of well-publicized, spectacular
 +
events compared with more commonplace ones; this is a well-understood phenomenon in
 +
the literature of risk assessment and leads to the truism that when statistics plays folklore,
 +
folklore always wins in a rout.”
 +
<div align=right>-- Donald Kennedy (former president of Stanford University), ''Academic Duty'', Harvard University Press, 1997, p.17</div>
 +
 
 +
----
 +
 
 +
"Using scientific language and measurement doesn’t prevent a researcher from conducting flawed experiments and drawing wrong conclusions — especially when they confirm preconceptions."
 +
 
 +
<div align=right>-- Blaise Agüera y Arcas, Margaret Mitchell and Alexander Todoorov, quoted in: The racist history behind facial recognition, ''New York Times'', 10 July 2019</div>
 +
 
 +
==In progress==
 +
[https://www.nytimes.com/2018/11/07/magazine/placebo-effect-medicine.html What if the Placebo Effect Isn’t a Trick?]<br>
 +
by Gary Greenberg, ''New York Times Magazine'', 7 November 2018
 +
 
 +
[https://www.nytimes.com/2019/07/17/opinion/pretrial-ai.html The Problems With Risk Assessment Tools]<br>
 +
by Chelsea Barabas, Karthik Dinakar and Colin Doyle, ''New York Times'', 17 July 2019
 +
 
 +
==Hurricane Maria deaths==
 +
Laura Kapitula sent the following to the Isolated Statisticians e-mail list:
 +
 
 +
:[Why counting casualties after a hurricane is so hard]<br>
 +
:by Jo Craven McGinty, Wall Street Journal, 7 September 2018
 +
 
 +
The article is subtitled: Indirect deaths—such as those caused by gaps in medication—can occur months after a storm, complicating tallies
 
   
 
   
"The researchers asked 180 people familiar with the station, or working there, with an average age of 55, about the clock: 173 knew it was stopped, and 160 said it had been since 1980. What's more, 127 claimed they had seen it stuck on 10.25 ever since the explosion, including all 21 railway employees. In a similar study published last year, 40% of 150 UK participants claimed to remember seeing closed circuit television footage of the moment of the explosion on the bus in Tavistock Square on 7 July 2005. No such footage exists."
+
Laura noted that
 +
:[https://www.washingtonpost.com/news/fact-checker/wp/2018/06/02/did-4645-people-die-in-hurricane-maria-nope/?utm_term=.0a5e6e48bf11 Did 4,645 people die in Hurricane Maria? Nope.]<br>
 +
:by Glenn Kessler, ''Washington Post'', 1 June 2018
  
Discussion
+
The source of the 4645 figure is a [https://www.nejm.org/doi/full/10.1056/NEJMsa1803972 NEJM article].  Point estimate, the 95% confidence interval ran from 793 to 8498.
1.  Goldacre is an excellent writer who specializes in pointing out how statistics is misused in science.  Go to [http://browse.guardian.co.uk/search?search=goldacre&year=2009&sitesearch-radio=guardian&go-guardian=Search here] for his 2009 contributionsTo get to previous years merely change the "9" to "8" or "7" etc.
 
2.  One would imagine that those closest to an incident would have the best memory but de Vito points out: “From the 173 people who knew that at the time of testing the clock was stopped, a subgroup of 56 citizens who regularly take part in the annual official commemoration of the event has been further considered: only six (11%) of them correctly remember that the clock had been working in the past.”
 
3.  Memories can be repressed as well as false.  Go to [http://www.guidetopsychology.com/repressn.htm here] for a discussion of repressed memory relating to child abuse; specifically, you will find
 
1.Smile Intensity and Divorce
 
  
Is there a connection between positive expressive behavior, as seen by facial photographs, and success in avoiding divorce?  According to http://www.livescience.com/culture/090414-smile-marriage.html Moskowitz], “If you want to know whether your marriage will survive, look at your spouse's yearbook photos. Psychologists have found that how much people smile in old photographs can predict their later success in marriage.”  This claim is based on a study headed by Matthew Hertenstein detailed in the April 5 issue of the journal Motivation and Emotion.
+
President Trump has asserted that the actual number is
The table below is taken from Hertenstein’s publication. Study 1, Sample 1 involves alumni who were psychology majors at a particular university; Study 1, Sample 2 involves alumni from the same university who were not psychology majors. In each instance, the participants submitted yearbook photos which were judged for smile intensity and whether or not the participants were divorced or still married. Study 2 is similar but involved older members of the community who submitted photos from decades past.
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[https://twitter.com/realDonaldTrump/status/1040217897703026689 6 to 18].
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The ''Post'' article notes that Puerto Rican official had asked researchers at George Washington University to do an estimate of the death toll.  That work is not complete.
 +
[https://prstudy.publichealth.gwu.edu/ George Washington University study]
 +
 
 +
:[https://fivethirtyeight.com/features/we-still-dont-know-how-many-people-died-because-of-katrina/?ex_cid=538twitter We sttill don’t know how many people died because of Katrina]<br>
 +
:by Carl Bialik, FiveThirtyEight, 26 August 2015
 +
 
 +
----
 +
[https://www.nytimes.com/2018/09/11/climate/hurricane-evacuation-path-forecasts.html These 3 Hurricane Misconceptions Can Be Dangerous. Scientists Want to Clear Them Up.]<br>
 +
[https://journals.ametsoc.org/doi/abs/10.1175/BAMS-88-5-651 Misinterpretations of the “Cone of Uncertainty” in Florida during the 2004 Hurricane Season]<br>
 +
[https://www.nhc.noaa.gov/aboutcone.shtml Definition of the NHC Track Forecast Cone]
 +
----
 +
[https://www.popsci.com/moderate-drinking-benefits-risks Remember when a glass of wine a day was good for you? Here's why that changed.]
 +
''Popular Science'', 10 September 2018
 +
----
 +
[https://www.economist.com/united-states/2018/08/30/googling-the-news Googling the news]<br>
 +
''Economist'', 1 September 2018
 +
 
 +
[https://www.cnbc.com/2018/09/17/google-tests-changes-to-its-search-algorithm-how-search-works.html We sat in on an internal Google meeting where they talked about changing the search algorithm — here's what we learned]
 +
----
 +
[http://www.wyso.org/post/stats-stories-reading-writing-and-risk-literacy Reading , Writing and Risk Literacy]
 +
 
 +
[http://www.riskliteracy.org/]
 +
-----
 +
[https://twitter.com/i/moments/1025000711539572737?cn=ZmxleGlibGVfcmVjc18y&refsrc=email Today is the deadliest day of the year for car wrecks in the U.S.]
 +
 
 +
==Some math doodles==
 +
<math>P \left({A_1 \cup A_2}\right) = P\left({A_1}\right) + P\left({A_2}\right) -P \left({A_1 \cap A_2}\right)</math>
  
Discussion
+
<math>P(E)  = {n \choose k} p^k (1-p)^{ n-k}</math>
  
1. In the above table, a two sample t-test of means (“M”) is carried out for each row.  Pick a row and verify degrees of freedom (“df”), the value of t and the p-value (“p”).  Note that “p values are one-tailed given the directional hypothesis of the studies.”
+
<math>\hat{p}(H|H)</math>
  
2. While p-value is useful to some extent, “effect size” may be of more interest.  The last column, “r” signifies that some sort of correlation is taking place; it is sometimes called the point-biserial correlation coefficient.  This correlation is between the independent dichotomous variable and the dependent variable (smile intensity).  According to the psychology literature, it is given by
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<math>\hat{p}(H|HH)</math>
  
+
==Accidental insights==
Where:
 
rpbi = point-biserial correlation coefficient
 
Mp = whole-test mean for those who stay married
 
Mq = whole-test mean for those who get divorced
 
St = standard deviation for all concerned
 
p = proportion of those who stay married (i.e., those coded as 1s)
 
q = proportion of those who get divorced (i.e., those coded as 0s)
 
  
Use this formula and Pick a row to verify the value in the table for “r”—ignore the sign.
+
My collective understanding of Power Laws would fit beneath the shallow end of the long tail. Curiosity, however, easily fills the fat end.  I long have been intrigued by the concept and the surprisingly common appearance of power laws in varied natural, social and organizational dynamics.  But, am I just seeing a statistical novelty or is there meaning and utility in Power Law relationships? Here’s a case in point.
  
3. Clearly, these results are for a sample.  Speculate on what you would need to know of the characteristics of the participants in order to infer to a larger population.
+
While carrying a pair of 10 lb. hand weights one, by chance, slipped from my grasp and fell onto a piece of ceramic tile I had left on the carpeted floor. The fractured tile was inconsequential, meant for the trash.
 +
<center>[[File:BrokenTile.jpg | 400px]]</center>
 +
As I stared, slightly annoyed, at the mess, a favorite maxim of the Greek philosopher, Epictetus, came to mind: “On the occasion of every accident that befalls you, turn to yourself and ask what power you have to put it to use.”  Could this array of large and small polygons form a Power Law? With curiosity piqued, I collected all the fragments and measured the area of each piece.
  
4.  Although the table is informative as to means and standard deviations, why would boxplots for each row be useful?
+
<center>
 +
{| class="wikitable"
 +
|-
 +
! Piece !! Sq. Inches !! % of Total
 +
|-
 +
| 1 || 43.25 || 31.9%
 +
|-
 +
| 2 || 35.25 ||26.0%
 +
|-
 +
|  3 || 23.25 || 17.2%
 +
|-
 +
| 4 || 14.10 || 10.4%
 +
|-
 +
| 5 || 7.10 || 5.2%
 +
|-
 +
| 6 || 4.70 || 3.5%
 +
|-
 +
| 7 || 3.60 || 2.7%
 +
|-
 +
| 8 || 3.03 || 2.2%
 +
|-
 +
| 9 || 0.66 || 0.5%
 +
|-
 +
| 10 || 0.61 || 0.5%
 +
|}
 +
</center>
 +
<center>[[File:Montante_plot1.png | 500px]]</center>
 +
The data and plot look like a Power Law distribution. The first plot is an exponential fit of percent total area. The second plot is same data on a log normal format. Clue: Ok, data fits a straight line.  I found myself again in the shallow end of the knowledge curve. Does the data reflect a Power Law or something else, and if it does what does it reflect?  What insights can I gain from this accident? Favorite maxims of Epictetus and Pasteur echoed in my head:
 +
“On the occasion of every accident that befalls you, remember to turn to yourself and inquire what power you have to turn it to use” and “Chance favors only the prepared mind.”
  
5. According to Moskowitz, but not mentioned in the paper itself by Hertenstein, “Overall, the results indicate that people who frown in photos are five times more likely to get a divorce than people who smile.”  This comes about by looking at the highest scorers--who turn out to be mostly still married--compared to the lowest scorers who turn out usually to be those who are divorced.  Why is this quotation featured rather than the above table?
+
<center>[[File:Montante_plot2.png | 500px]]</center>
6.  For those who would like to improve their “smile intensity” of their photos, here is what the paper itself says the measurement process is:
 
 
   
 
   
 +
My “prepared” mind searched for answers, leading me down varied learning paths. Tapping the power of networks, I dropped a note to Chance News editor Bill Peterson. His quick web search surfaced a story from ''Nature News'' on research by Hans Herrmann, et. al. [http://www.nature.com/news/2004/040227/full/news040223-11.html Shattered eggs reveal secrets of explosions].  As described there, researchers have found power-law relationships for the fragments produced by shattering a pane of glass or breaking a solid object, such as a stone. Seems there is a science underpinning how things break and explode; potentially useful in Forensic reconstructions.
 +
Bill also provided a link to [http://cran.r-project.org/web/packages/poweRlaw/vignettes/poweRlaw.pdf a vignette from CRAN] describing a maximum likelihood procedure for fitting a Power Law relationship. I am now learning my way through that.
  
 +
Submitted by William Montante
  
http://www.springerlink.com/content/h0922623gp621407/fulltext.html
+
----
pened.
 
2. An event that you falsely remember can be psychologically equivalent to an event that really did happen.
 
The clock in Milan worked for another 16 years.  Adults report abuse which supposedly took place often decades previous.  Use Google to see a discussion of some of these legal cases and their outcomes.
 
4.  Is there anything you used to recall vividly that you now doubt actually occurred?
 

Latest revision as of 20:58, 17 July 2019


Forsooth

Quotations

“We know that people tend to overestimate the frequency of well-publicized, spectacular events compared with more commonplace ones; this is a well-understood phenomenon in the literature of risk assessment and leads to the truism that when statistics plays folklore, folklore always wins in a rout.”

-- Donald Kennedy (former president of Stanford University), Academic Duty, Harvard University Press, 1997, p.17

"Using scientific language and measurement doesn’t prevent a researcher from conducting flawed experiments and drawing wrong conclusions — especially when they confirm preconceptions."

-- Blaise Agüera y Arcas, Margaret Mitchell and Alexander Todoorov, quoted in: The racist history behind facial recognition, New York Times, 10 July 2019

In progress

What if the Placebo Effect Isn’t a Trick?
by Gary Greenberg, New York Times Magazine, 7 November 2018

The Problems With Risk Assessment Tools
by Chelsea Barabas, Karthik Dinakar and Colin Doyle, New York Times, 17 July 2019

Hurricane Maria deaths

Laura Kapitula sent the following to the Isolated Statisticians e-mail list:

[Why counting casualties after a hurricane is so hard]
by Jo Craven McGinty, Wall Street Journal, 7 September 2018

The article is subtitled: Indirect deaths—such as those caused by gaps in medication—can occur months after a storm, complicating tallies

Laura noted that

Did 4,645 people die in Hurricane Maria? Nope.
by Glenn Kessler, Washington Post, 1 June 2018

The source of the 4645 figure is a NEJM article. Point estimate, the 95% confidence interval ran from 793 to 8498.

President Trump has asserted that the actual number is 6 to 18. The Post article notes that Puerto Rican official had asked researchers at George Washington University to do an estimate of the death toll. That work is not complete. George Washington University study

We sttill don’t know how many people died because of Katrina
by Carl Bialik, FiveThirtyEight, 26 August 2015

These 3 Hurricane Misconceptions Can Be Dangerous. Scientists Want to Clear Them Up.
Misinterpretations of the “Cone of Uncertainty” in Florida during the 2004 Hurricane Season
Definition of the NHC Track Forecast Cone


Remember when a glass of wine a day was good for you? Here's why that changed. Popular Science, 10 September 2018


Googling the news
Economist, 1 September 2018

We sat in on an internal Google meeting where they talked about changing the search algorithm — here's what we learned


Reading , Writing and Risk Literacy

[1]


Today is the deadliest day of the year for car wrecks in the U.S.

Some math doodles

<math>P \left({A_1 \cup A_2}\right) = P\left({A_1}\right) + P\left({A_2}\right) -P \left({A_1 \cap A_2}\right)</math>

<math>P(E) = {n \choose k} p^k (1-p)^{ n-k}</math>

<math>\hat{p}(H|H)</math>

<math>\hat{p}(H|HH)</math>

Accidental insights

My collective understanding of Power Laws would fit beneath the shallow end of the long tail. Curiosity, however, easily fills the fat end. I long have been intrigued by the concept and the surprisingly common appearance of power laws in varied natural, social and organizational dynamics. But, am I just seeing a statistical novelty or is there meaning and utility in Power Law relationships? Here’s a case in point.

While carrying a pair of 10 lb. hand weights one, by chance, slipped from my grasp and fell onto a piece of ceramic tile I had left on the carpeted floor. The fractured tile was inconsequential, meant for the trash.

BrokenTile.jpg

As I stared, slightly annoyed, at the mess, a favorite maxim of the Greek philosopher, Epictetus, came to mind: “On the occasion of every accident that befalls you, turn to yourself and ask what power you have to put it to use.” Could this array of large and small polygons form a Power Law? With curiosity piqued, I collected all the fragments and measured the area of each piece.

Piece Sq. Inches % of Total
1 43.25 31.9%
2 35.25 26.0%
3 23.25 17.2%
4 14.10 10.4%
5 7.10 5.2%
6 4.70 3.5%
7 3.60 2.7%
8 3.03 2.2%
9 0.66 0.5%
10 0.61 0.5%
Montante plot1.png

The data and plot look like a Power Law distribution. The first plot is an exponential fit of percent total area. The second plot is same data on a log normal format. Clue: Ok, data fits a straight line. I found myself again in the shallow end of the knowledge curve. Does the data reflect a Power Law or something else, and if it does what does it reflect? What insights can I gain from this accident? Favorite maxims of Epictetus and Pasteur echoed in my head: “On the occasion of every accident that befalls you, remember to turn to yourself and inquire what power you have to turn it to use” and “Chance favors only the prepared mind.”

Montante plot2.png

My “prepared” mind searched for answers, leading me down varied learning paths. Tapping the power of networks, I dropped a note to Chance News editor Bill Peterson. His quick web search surfaced a story from Nature News on research by Hans Herrmann, et. al. Shattered eggs reveal secrets of explosions. As described there, researchers have found power-law relationships for the fragments produced by shattering a pane of glass or breaking a solid object, such as a stone. Seems there is a science underpinning how things break and explode; potentially useful in Forensic reconstructions. Bill also provided a link to a vignette from CRAN describing a maximum likelihood procedure for fitting a Power Law relationship. I am now learning my way through that.

Submitted by William Montante