[R] p-values with pvclust

syrvn mentor_ at gmx.net
Tue Aug 10 14:44:52 CEST 2010


if you look at the first image (Image1)  you see that there are 2 main
clusters 7 and 8
I wanted to use pvclust to calculate a p-value whether these clusters are
due to chance
or statistically significant. Unfortunately pvclust does not provide a
p-value for the first
brunch (7 and 8).

So I added a row to my matrix which is very different to the rest of the
data to create an additional
brunch. See image here 
http://r.789695.n4.nabble.com/file/n2319732/Image2.png . I finally got my
p-value for the brunch (7 and 8) which is 98 (9).

I was happy to see that the p-value was significant until I realised that if
I add an additional brunch which
is not that different from the rest but still cluster in a sperate cluster
(see image here  http://r.789695.n4.nabble.com/file/n2319732/Image3.png )
the p-value is changing and not significant any longer (84).

I was wondering why this happens because I thought that for each brunch the
p-value is calculated independently?

Does anybody know how to get a correct p-value for the first brunch (7 and
8) maybe without adding an additional brunch?

Best regards
View this message in context: http://r.789695.n4.nabble.com/p-values-with-pvclust-tp2319732p2319732.html
Sent from the R help mailing list archive at Nabble.com.

More information about the R-help mailing list