Dear FSL experts,
I'm conducting a 2 sample t-test on 20 subjects, each scanned under 3 conditions A, B, C. I'm interested in finding the affects of 1 condition vs each others. So 3 EVs are set for each condition. I enter subject 1 with the conditions A, B, C and then subject 2 with the conditions A, B, C, ect. until subject 20 (each input is individual FEAT result at first level) like below:
Subject1: 1 0 0
Subject1: 0 1 0
Subject1: 0 0 1
Subject2: 1 0 0
Subject2: 0 1 0
Subject2: 0 0 1
…
Subject20: 0 0 1
I was planning to compare these conditions with these contrasts:
C1 (A>B): 1 -1 0
C2 (A<B): -1 1 0
C3 (A>C): 1 0 -1
C4 (A<C): -1 0 1
C5 (B>C): 0 1 -1
C6 (B<C): 0 -1 1
Should I split the Evs into 3 groups according to the conditions? Because I got 2 different results for 2 cases of designs, I’m concerned that could the different cross-subject variance change the result? Or the design could change the statistical test from two sample t-test onto triple t-test?
Thanks in advance,
Kim
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