----- Original Message -----
From: haytham siala <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, February 09, 2000 2:12 PM
Subject: ANOVA data
> Can I perform an ANOVA on standardized variables?
>---------------------------------------------------------------------------
If you standardize the complete data set based on the overall mean of the
complete data set and the standarad deviation of the whole data set, then
there would be no effect on the conclusions as to significance. What you are
doing is arriving at a total sum of squares of unity.
The magnetude of the effects of each variable and variable interaction as
derived from the basic experimental design will be different It may be
difficult to work back to the original scales.
Standardization with respect to the mean should be done when you are doing
the ANOVA in EXCEL (or other canned programs), since the accuracy of results
is much improved. (EXCEL algorithms are very sensitive to the overall mean
value.)
Standardization with respect to the variance is not necessary, except in
regression.
The canned software, if it is good should do the standardization internally,
and back calculate values to the scales of the input variables. In that case
there would be no difference in the results.
DAH
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This list is open to everyone. Occasionally, people lacking respect
for other members of the list send messages that are inappropriate
or unrelated to the list's discussion topics. Please just delete the
offensive email.
For information concerning the list, please see the following web page:
http://jse.stat.ncsu.edu/
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