## Mean and Standard Deviation

*February 13, 2011 at 11:27 pm* *
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As a follow-up to yesterday’s post, here’s a poem titled *Mean and SD* by Norman Chansky, professor emeritus at Temple University. Ostensibly, the poem first appeared in the Journal of Irreproducible Results, though I was unable to find an exact citation.

The mean is a measure of location,

The center of a population.

If at random a score you drew,

The mean’s the most likely score you’d view.You can compute the mean in your slumber:

Sum the scores, and divide by the number.

At the mean, sample scores converge;

From the mean, these scores diverge.

Near the mean, the scores are many.

In the tails, there are hardly any.But to measure a distribution’s variation,

From the mean, find each score’s deviation.

Each difference ofDscore, now you square.

Sum allDscores, all scores’ share.

Now this sum, divide byN.

That’sV, the variance, then.The square root of

Vis calledSD,

The gauge of a trait’s variability.

We’ve found two moments of a distribution,

Developed from each score’s contribution.Picturing a universe, try to see:

Its center, the mean; its orbit,SD.

Entry filed under: Uncategorized. Tags: mean, Norman Chansky, postaweek2011, standard deviation, statistics, variance.

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