R help - Apr 2009 - How to set the number of multiple comparisons (Bonferroni-Holm)

Hello.
We have a question concerning the nonparametric analysis of a dataset, which
resulted in rejection of the null hypothesis (Kruskal-Wallis-test = H-test).
In order to find out which sample means actually are statistically
different, we want to do multiple comparisons with the Wilcoxon rank sum
test (= U-test); the p-level should be corrected according to
Bonferroni-Holm. Thus we decided to use the following R syntax:

pairwise.wilcox.test (x, g, p.adjust.method = "holm", paired = FALSE)

Since there are 22 sample means in the dataset, lots of comparisons are
possible and the Bonferroni-Hom correction method would apply very low
p-levels. Since we are only interested in some (m = 11) of these
comparisons, we would like to set the number of comparisons, so that the
p-level won?t be corrected too much. We found the following R-syntax:

p.adjust(p, method = p.adjust.methods, n = length (p))

with 'n' being the "number of comparisons". So can we set the
number of
comparisons we are interested in here? And where do we have to put this
syntax - before the pairwise.wilcox.test-syntax? And what shall we set for
'p' in this syntax?

Thank you for your help.
Kind regards,
Christine Hellmann and Rabea Sutter
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