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Re: "Paired" test for 3 variables

Posted by Swank, Paul R on Jun 08, 2009; 2:54pm
URL: http://spssx-discussion.165.s1.nabble.com/Paired-test-for-3-variables-tp1089169p1089170.html

While they may not be precisely what you would call repeated measures, if you wish to compare related observations then a repeated measures ANOVA or mixed model would be the best approach for the omnibus test. Follow-up up to a significant omnibus test would be by protected paired t-tests or either pairwise differences or contrasts.

Dr. Paul R. Swank,
Professor and Director of Research
Children's Learning Institute
University of Texas Health Science Center-Houston


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Hugh Sandoz
Sent: Sunday, June 07, 2009 10:22 AM
To: [hidden email]
Subject: "Paired" test for 3 variables

Hi,

I've conducted a research in which each sample/respondent is tested for 3
attributes (how much he/she likes A, B and C). A, B and C are not repeated
measurements of the same thing, but measurements of different things from
the same person. I need to compare the means of A, B and C, and see which is
larger/smaller than which (basically multiple pairwise comparisons).

Because the responses are matched by respondents, should I first test for
independence of A, B and C before deciding if I should use ANOVA
(independent variables) or something like a paired t-test (but for 3
variables)? Or should I assume that they are dependent and directly go for
the latter?

And how would I do a test for 3 dependent/matched variables? If I'm not
wrong, repeated-measures one-way ANOVA only works for repeated measures of
the same thing. Should I use multivariate analysis of variance (MANOVA)?

I've tried running MANOVA on SPSS with 3 dependent variables and no fixed
factors - it's given me significant results for Pillai's Trace, Wilk's
Lambda, Hotelling's Trace and Roy's Largest  Root. However, I have no idea
what these results mean despite looking up the SPSS manual, nor do I know
which mean is bigger than which. As far as I can tell, no pairwise
comparisons have been conducted. Can anyone please advise?

Thanks in advance.
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