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.
There seems to be no point in standardizing all scores - I don't get rid of my confound and the ANOVA turns out basically the same as the ANOVA on raw data. Hope you can help.
Thanks,
Anders Hojen
