ttperm: A simple function to compute a permutation t-test.
Description
The data matrix, x, with two-level factor, fac, is used
to compute t-tests. The values of fac are permuted B
times and the complete set of t-tests is performed for each
permutation.
Usage
ttperm(x, fac, B = 100, tsO = TRUE)
Arguments
x
A data matrix. The number of columns should be the same as
the length of fac.
fac
A factor with two levels.
B
An integer specifying the number of permutations.
tsO
A logical indicating whether to compute only the t-test
statistic for each permuation. If FALSE then p-values are
also computed - but this can be very slow.
Value
A list, the first element is named obs and contains the true,
observed, values of the t-statistic. The second element is named
ans and contains a list of length B containing the
different permuations.
Details
Not much more to say. Probably there is a generic function somewhere,
but I could not find it.