[R] Adjusting p values of a matrix

From: January Weiner <january.weiner_at_mpiib-berlin.mpg.de>
Date: Mon, 04 Apr 2011 17:02:28 +0200


Dear all,

I have an n x n matrix of p-values. The matrix is symmetrical, as it describes the "each against each" p values of correlation coefficients.

How can I best correct the p values of the matrix? Notably, the total number of the tests performed is n(n-1)/2, since I do not test the correlation of each variable with itself. That means, I only want to correct one half of the matrix, not including the diagonal. Therefore, simply writing

pmat <- p.adjust( pmat, method= "fdr" )
# where pmat is an n x n matrix

...doesn't cut it.

Of course, I can turn the matrix in to a three column data frame with n(n-1)/2 rows, but that is slow and not elegant.

regards,
j.

-- 
-------- Dr. January Weiner 3 --------------------------------------
Max Planck Institute for Infection Biology
Charitéplatz 1
D-10117 Berlin, Germany
Web   : www.mpiib-berlin.mpg.de
Tel     : +49-30-28460514

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Received on Mon 04 Apr 2011 - 15:51:37 GMT

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