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repeated measures: random effects versus manova

To: jmp-l@lists.biostat.wustl.edu
Subject: repeated measures: random effects versus manova
From: Michael Bailey <jm-bailey@northwestern.edu>
Date: Tue, 30 May 2006 12:40:40 -0500
I am familiar with two ways of analyzing repeated measures effects in jmp. One of them uses a vertically-organized file structure, with multiple lines per subject, and uses subject as a random factor. The other uses a horizontally-organized file structure, with MANOVA. (Fit Model: MANOVA Personality: Choose Response: Coompound; interaction effects) The former approach makes sense to me and I can get it to work. However, I have the same dataset organized both ways, and I cannot get the MANOVA approach to reproduce the results I obtain in the random effects approach. Maybe it's not supposed to? And I don't know MANOVA, so maybe I'm not looking in the right way. If anyone is sufficiently interested and knowledgeable, I'd appreciate your input. I'm attaching the two datasets in case you want to check 'em out.

In the horizontal file, the four variables, prefleft, prefright, nonleft, nonright represent the repeated measures. The two within- subjects variables are laterality (left versus right) and preference (pref versus nonpref). So laterality is the faster moving variable. Orientation is a between-subjects factor. As an example of a result I would like to find in the MANOVA, in the random effects analysis (with all main effects and interactions), I get a significant interaction for Prefnon*Orientation, F(1,59)=10.8, P=.0017.


Attachment: amygdalahorizontal.jmp
Description: application/applefile

Attachment: amygdalahorizontal.jmp
Description: Binary data


Attachment: amygdalavertical.jmp
Description: application/applefile

Attachment: amygdalavertical.jmp
Description: Binary data

Michael Bailey
jm-bailey@northwestern.edu


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