[BioC] multtest problem...
huber at ebi.ac.uk
Fri Apr 29 12:06:14 CEST 2005
your mail is not very clear about the distinction between test
statistics and p-value, and perhaps this is where your confusion comes from?
There is no reason why the two numbers you state in your mail should be
equal, they are different things.
Have a look as well at the function rowttests in the develop version of
"genefilter", for a fast and userfriendly approach to doing t-tests for
each row of an exprSet.
Dipl.-Ing. Johannes Rainer wrote:
> i used the mt.teststat function from the package multtest and wonder why
> the p values that the function calculates differ from those i get using
> the wilcox.test or t.test function.
> i tried it with the golub data set (data(golub)) and
> returns a p-value = 0.8987
> while teststat<-mt.teststat(golub,golub.cl,test="wilcoxon")
> teststat = 1.75419
> i thought that the mt.teststat funciton uses simple t tests or wilcox
> test to calculate p values...
> perhaps i am wrong with the class labels?
> from the help i understood, that if i have two groups in my samples i
> submit as classlabels for examples c(0,0,0,1,1,1) and this means that
> the first 3 columns of my data correspond to group 0 and the other 3 to
> group 1. is this correct?
> thanks, jo
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