Standard Deviation Formula without Mean

Date: 10/03/2002 at 22:41:30
From: Ryan Mabry
Subject: Standard Deviation without Mean

Is there a formula for calculating the standard deviation without 
using the mean?

Date: 10/10/2002 at 09:01:06
From: Doctor Pepper
Subject: Re: Standard Deviation without Mean

Hi Ryan -

To compute the standard deviation without computing the mean, you 
can use this formula:
           
  std dev = sqrt [(B - A^2/N)/N]

where

  A is the sum of the data values;
 
  B is the sum of the squared data values;

  N is the number of data values.

Best wishes!

- Doctor Pepper, The Math Forum
  <http://mathforum.org/dr.math/