[BioC] T test across columns

[Naomi Altman]

The absolutely simplest thing would be

t.test(C[,1],C[,4])
t.test(C[,2],C[,5])
t.test(C[,3],C[,6])

Why spend a lot of time figuring out clever ways to do something, when you 
only want to do 3 tests?

--Naomi

p.s. If you need to repeat this on many matrices, C, write a small function 
with the 3 lines above.

At 03:59 PM 7/26/2005, mark salsburg wrote:
> > ok I created a matrix C with
> >
> > A   B  D    A1   B1    D1
> > ..................................
> > .................................
> >
> > the columns contain the gene expression values for tissues...
> >
> > I ran the following t.test:
> >
> > apply(C, 1, function(x) t.test( x[1:3], x[4,6] )$p.value )
> >
> > which outputs out 16063 pvalues (the number of rows)
> >
> > I just want to output 3 pvalues showing if A's column is different from 
> A1 etc..
> >
> > any help would be great.. thank you..
> >
>
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Naomi S. Altman                                814-865-3791 (voice)
Associate Professor
Bioinformatics Consulting Center
Dept. of Statistics                              814-863-7114 (fax)
Penn State University                         814-865-1348 (Statistics)
University Park, PA 16802-2111