Dear SPMers,
My PET study consists of 2 groups (group n° 1: 17 subjects ; group n° 2: 12
subjects) and 5 conditions(rest and 4 language tasks). I used flexible
factorial design with 3 factors : subject, group, condition. In the "Main
effect and interaction" menu, I entered the interaction group x condition
(Factor number [2 3]). I got the group by condition matrix (attached file).
However, basic contrast (language vs rest in group 1) did not show any
significant activation.
Then, I used the same flexible factorial design, I entered the interaction
subject x condition (Factor number [1 3]) and I got the subject by condition
matrix (attached file). Same contrast (language vs rest in group 1)with this
matrix gave hudge significant activations.
Why does these two matrix give so different results ? Is the
subject by condition matrix suitable for this experiment ?
Thanks a lot !
Evelyne
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