[BioC] p-values for multtest

[Marcus Davy]

Ann,
heres a function to extract a vector of dfs using the input objects X,
and classlabel 
inputs for mt.teststat.

welchdf <- function(X, classlabel)
  {
    varx1 <- apply(X[,as.logical(classlabel)], 1, var)
    varx2 <- apply(X[,!as.logical(classlabel)], 1, var)
    n <- table(classlabel)
    df <-
(((varx1/n[1])+varx2/n[2])^2)/(((varx1/n[1])^2)/(n[1]-1)+((varx2/n[2])^2)/(n[2]-1))
    df
  }

It gives similar figures to
t.test(x,y, var.equal=F)$parameter
for any row in X.

marcus

>>> Ann Hess <hess at stat.colostate.edu> 1/10/2003 8:41:39 AM >>>
I am using mt.teststat (multtest) to obtain the teststatistics for
Welch
t-tests.  I was wondering if there is a way to get the Satterthwaite
(Welch)
df for the tests using multtest.

Any help would be appreciated.

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