Linda -
I'm assuming you intended to say the mean of the absolute values of the
deviation scores, right? Of course if you sum the deviation scores before
getting the absolute values, they will sum to zero...
Judith Roberts
City College of San Francisco
On Fri, 22 Sep 2000 [EMAIL PROTECTED] wrote:
> Greetings to all stats historians out there
>
> A student asked today, upon starting discussion of the standard deviation,
> why we do not simply use the average (mean) absolute value of the deviation
> scores, rather than taking the square root of the sum of squares. Many
> introductory stats texts provide no explicit rationale or history of the
> standard deviation formula. The mean absolute value of the deviation scores
> would seem to be a reasonable descriptive measure of the variability of the
> scores.
>
> TIA for any help you can provide.
>
> Linda Tollefsrud
> University of Wisconsin - Barron County
> 1800 College Drive
> Rice Lake, WI 54868-2497
> [EMAIL PROTECTED]
> (715) 234-8176 ext. 5417
>
