[R] Repeated Measures MANOVA in R
Chuck Cleland
ccleland at optonline.net
Thu Nov 9 10:45:33 CET 2006
A. Bolu Ajiboye wrote:
> Can R do a repeated measures MANOVA and tell what dimensionality the statistical variance occupies?
>
> I have been using MATLAB and SPSS to do my statistics. MATLAB can do ANOVAs and MANOVAs. When it performs a MANOVA, it returns a
> parameter d that estimates the dimensionality in which the means lie. It also returns a vector of p-values, where each p_n tests
> the null hypothesis that the mean vectors lie in an n-1 dimensional space (0-D space implies same vector, 1-D space implies scaled
> vectors that point in the same direction, etc...). However, MATLAB does not do repeated measures MANOVA. SPSS can do repeated
> measures MANOVA but it does not return this dimension output. Hence, I'm trying to find an environment that will allow me to do
> repeated measures MANOVA and determine the dimensionality of the space, before I spend several weeks trying to learn it.
>
> I know the dimensionality parameter is based upon the eigenvalues of the ratio of the different SSCP (sum of squares and cross
> products) matrices, but a) I'm not sure how to calculate the SSCP matrices for repeated measures MANOVA, and b) once I get these
> eigenvalues and convert them a Pillai-Bartlett or Wilk's-Lambda value, I don’t know how to convert to an f-statistic.
>
> Does anybody know how to do this or has repeated measures MANOVA in R (while returning the dimensionality parameter)? Thanks in
> advance for your help.
I don't know about the dimensionality parameter, but have a look at
anova.mlm(). In particular, you might want to run example(anova.mlm)
and study the output. Also, you might look at SSD() and
summary.manova() in package stats.
> Bolu
>
>
>
> --
>
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--
Chuck Cleland, Ph.D.
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