Dear spm-list,
I have built a flexible factorial design for two groups with two
sessions (G1S1, G1S2, G2S1, G2S2) and fiven the following f-contrast
weights for the interaction Group x Session:
[1 -1 -1 1
-1 1 1 -1]
Now I would like to add a third group to the design, so it would be
G1S1, G1S2, G2S1, G2S2, G3S1, G3S2. Im leaving out the main effects on
purpose, so I would just like to model the interaction.
I'm not sure how to define the contrast weights though. Could somebody
help me? Thanks!
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