I am new to R and I suspect my problem is easily solved, but I haven't
been able to figure it out without using loops. I am trying to
implement Blair & Karniski's (1993) permutation test. I've included a
sample data frame below. This data frame represents the conditional
means (C1, C2) for 3 subjects in 2 consecutive samples of a continuous
data set (e.g. ERP waveform). Each sample includes all possible
permuations of the subject means (2^N), which is 8 in this case.
The problem: I need to run a paired t-test on each SampleXPermutation
set and save the maximum t-value obtained for each sample. The real
data set has 16 subjects (216 permutations) and 500 samples, which leads
to more than 32 million t-tests. I have a loop version of the program
working, but it would take a few weeks to complete the job and I was
hoping that someone could tell me how to do it faster?
thank you kindly,
Matthew Finkbeiner
--------------------------------
"Sample" "C1" "C2" "PermN"
1 5 8 perm1
1 4 3 perm1
1 6 4 perm1
2 2 6 perm1
2 3 1 perm1
2 7 4 perm1
1 8 5 perm2
1 3 4 perm2
1 6 4 perm2
2 6 2 perm2
2 1 3 perm2
2 7 4 perm2
1 5 8 perm3
1 3 4 perm3
1 6 4 perm3
2 2 6 perm3
2 1 3 perm3
2 7 4 perm3
1 8 5 perm4
1 4 3 perm4
1 4 6 perm4
2 6 2 perm4
2 3 1 perm4
2 4 7 perm4
1 5 8 perm5
1 4 3 perm5
1 4 6 perm5
2 2 6 perm5
2 3 1 perm5
2 4 7 perm5
1 8 5 perm6
1 3 4 perm6
1 4 6 perm6
2 6 2 perm6
2 1 3 perm6
2 4 7 perm6
1 5 8 perm7
1 3 4 perm7
1 4 6 perm7
2 2 6 perm7
2 1 3 perm7
2 4 7 perm7
1 8 5 perm8
1 4 3 perm8
1 6 4 perm8
2 6 2 perm8
2 3 1 perm8
2 7 4 perm8
--
Dr. Matthew Finkbeiner
Senior Lecturer & ARC Australian Research Fellow
Macquarie Centre for Cognitive Science (MACCS)
Macquarie University, Sydney, NSW 2109
Phone: +61 2 9850-6718
Fax: +61 2 9850-6059
Homepage: http://www.maccs.mq.edu.au/~mfinkbei
Lab Homepage: http://www.maccs.mq.edu.au/laboratories/action/
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