[FieldTrip] interaction within-subject indepsamplesT

[Kathrin Müsch]

Hello FieldTrip users,

I need your advice on how to correctly test the interaction effects in a 2x2 within-subject design with cluster-based randomization tests. I have two factors A and B with the levels a1/a2 and b1/b2. In addition, the number of trials in A are about twice as much as in B.

The procedure would be totally clear in a between-subject design (as in a previous post on the list: http://mailman.science.ru.nl/pipermail/fieldtrip/2011-January/003447.html) because I could easily compute the differences of the factor levels A_diff=a1-a2 and B_diff=b1-b2 and then run ft_freqstatistics on the differences. However, since I have to run the statistics across trials and not subjects I have independent samples and not dependent samples. If it is possible at all, how can I calculate the differences A_diff and B_diff across trials? Is it a problem that the number of trials are not equal?

Any help is appreciated!

Best,
Kathrin

_____________________________________
Kathrin Müsch

Dept. of Neurophysiology and Pathophysiology
University Medical Center Hamburg-Eppendorf
Martinistr. 52
20246 Hamburg
Germany
Phone: +49-40-7410-54680
Fax: +49-40-7410-57752
E-Mail: k.muesch at uke.uni-hamburg.de
_____________________________________


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