If all scores are centered on the grand mean, the ANOVA will be unaffected. But I think if the data are converted to z's by groups, then each group would have equal variance.

At 09:41 AM 6/2/2004, you wrote:
Since zs are a linear transformation of the raw data, I don't see how converting data to z will get rid of anything ...

At 07:29 PM 6/1/2004, you wrote:

Hello, I just joined this list - hope somebody can help me with this question.
I have a 2-way anova with one within- and one between-groups measure. There is a confound between the 3 levels of the within-groups measure that I can get rid of by converting to z-scores. However, If I standardized the three levels of the within-groups measure, the mean for all levels will, of course, be 0 in all 3 cases. This means that the main effect of this factor is neutralized. That is actually a good thing because I am only interested in the between-groups factor and in the interaction. My question is whether it is legitimate to do this.

Dennis Roberts [EMAIL PROTECTED] http://www.personal.psu.edu/users/d/m/dmr/droberts.htm

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