by Lawrence Mark Lesser
Statistics must be fast. . .
‘cause my newspaper gives numerical nuggets as “fast facts”
‘cause my doctor’s orders say STAT when she wants a test done now
‘cause velocity is a big feature of big data
‘cause some statisticians
do accelerated testing,
fast Fourier transforms,
or a Tukey’s quick test
‘cause statisticians
run studies,
run simulations,
and run tests (like a runs test)
and those who run are fast, even
in the long run
by Gill Marjorie Onate and Muzaffar Bhatti
University of Toronto Mississauga
Five, lucky, randomly chosen married couples.
They were pink elephants, may I add,
Were invited to the party of a lifetime,
They were good looking, not too bad.
But one couple looked different,
Shorter than all the rest.
Everyone called them “the outliers,”
Even so, they looked their best!
There may be a deviation from normality,
Hmm… In what way?
Only five lucky couples were chosen,
Therefore, a small sample size and “the outliers,” I would say!
The effect may be bigger. Should we rely on The Central Limit Theorem?
No way!
Along the path, they walked and walked,
Facing a fork up ahead.
“Which way should we go?” They talked and talked,
One elephant looked at the sign and read…
“To make it to the Wilcoxon Signed Rank Test Party,
You must pass this riddle:
Does height have over 20 possible values???
Pick quick, or you’re stuck in the middle.”
Left is “Yes” and right is “No”
“Hmm.. what’s the answer though?”
Pink elephants come in all different sizes!
Sizes come in all!
Big or small,
Short or tall!
Going left would be the right call!
Another sign at the fork up ahead,
“Oh boy, I’m nervous,” one said.
“Are the samples paired???
Yes or No?”
Of course they’re paired!
They’re all married, can’t you see?
“Let’s follow the ‘Yes’ path! It leads us to the Wilcoxon Signed Rank Test Party!”
“Yup, I agree!”
“Just curious,
What would have happened if we went down the “No” path?” one asked.
“It means we’re not paired, silly!
At the end of that path is the Wilcoxon Rank Sum Test.
It’s for the ones who are single
And ready to mingle!”
After long walks,
And after long talks,
They made it, finally!
Look at all the clocks!
It’s time! Get ready!
The countdown is starting,
“Woohoo! This is the best!”
3…2…1!!!
HAPPY WILCOXON SIGNED RANK TEST
Lyrics & Music © 2017 by Greg Crowther
CHORUS:
Inferential and descriptive:
different stats with different rules
Inferential and descriptive:
different goals and different tools.
What's the average height of students in this room, whom I can measure?
Here you are describing data that you've got.
What's the average height of students living in Australia?
Now you are inferring something you know not.
[REPEAT CHORUS]
When reporting variation in descriptive information,
interquartile range may be employed.
When reporting variation in inferential information,
standard error of the mean may fill the void.
[REPEAT CHORUS]
Lyrics © Mary McLellan may sing to the tune of the Eagles' "Hotel California"
Power is the probability
to reject the null (to reject the null)
if its false indeed
Power is the probability
to reject the null (to reject the null)
if its false indeed
Uncertainty is the prerequisite to gaining knowledge and frequently the result as well.
Edith Hamilton (1867 – 1963)