Date: Sep 18, 2008 3:34 PM
Author: Pat Ballew
Subject: Standard deviation Geometric construction

A few days ago I came across a patent for a machine that would calculate the standard deviation of a group of numbers from the pre-computer days.  It lead me to think that there must be a geometric construction to do the same thing, so I created one (using only three numbers) but it is totally generalizable to more... Lots of images so I put it on a blog at

There is even a pretty good cartoon that an associate sent me..

Pat Ballew,
Lakenheath UK
Elk Rapids, Michigan, USA