Standard Deviation

September 1st, 2011
math
Standard deviation is the average distance between each data point and the mean of the data. It's defined as:

Why isn't it:

That is, why is it the square root of the average of (x-mu)^2 instead of just the average of |x-mu|? How is the squared version more useful?

Update 2011-09-01 I had left out the square root on the standard deviation.

Comment via: google plus, facebook, substack

Recent posts on blogs I like:

Linkpost for May

Effective Altruism

via Thing of Things May 4, 2026

Fiddle Practice

For a while I wasn't learning how to play violin very well because whenever it was time to practice I didn't want to. I didn't really like practicing, because (1) it's boring, (2) I have better things to do, and (3) actually I guess there …

via Anna Wise's Blog Posts May 3, 2026

New Pony

I have a new pony. I got her from the Goodwill. Her name is "Rainbow" and her nickname is "Sparkles". We went the usual way, in the pink stroller. We went downstairs and I played with some of the toys. I found the pony in the toy area. …

via Nora Wise's Blog Posts May 3, 2026

more     (via openring)