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/

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Reply via email to