Posted by
Rich Ulrich on
Apr 12, 2011; 9:48pm
URL: http://spssx-discussion.165.s1.nabble.com/Factorial-ANOVA-with-Ranked-Data-tp4299119p4299214.html
> Date: Tue, 12 Apr 2011 16:21:12 -0500
> From:
[hidden email]
> Subject: Re: Factorial ANOVA with Ranked Data
> To:
[hidden email]
>
> There is a 2x2 factorial between subjects design, resulting in 4 cells with random assignment. Each subject is asked to make the rankings on each of 8 response options (which essentially ruins the ANOVA design).
Eight responses?
The main analysis should probably be performed on a composite
score, or a couple of scores. If you average even two scores
that are 1-8, you suppress the potential problem of interactions
which can be introduced by the natural bad scaling of ranks.
I could suggest doing a test, first, to see if anything shows
up. Why borrow trouble? If there are no main effects, there
is nothing to induce an artifactual interaction.
>
> I'm sort of intrigued by the problem of trying to force a parametric approach on nonparametric data, and whether it can be done.
>
One artificial way is to score the ranks as percentiles; then
score the percentiles to logit or normal. I am curious as to
whether anyone has references on doing that, since it has long
seemed pretty obvious to me but I have never seen it discussed.
--
Rich Ulrich
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