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:

I did a meditation and it sort of changed my personality?!

a trip report

via benkuhn.net November 8, 2026

The bad part about rape is all the rape

I have recently seen a lot of people casually refer to consensual non-consent orgies as “rape orgies”.

via Thing of Things November 6, 2026

“We should be more ambitious with the software we build”

Since early this year, Michael Malis (of pgrust) has been showing me interesting things he's done and saying [W]e should be more ambitious1 with the software we build There is, understandably, a lot of skepticism about projects like pgrust because there…

via Posts on October 24, 2026

more     (via openring)