Dear SPM-users,
I have a little question about my study design.
I want to compare 3 sub-groups on a 2-by-2 factorial design.
For comparison between two groups I use a
1 -1 -1 1 -1 1 1 -1
contrast to test for 3-way interaction
But what to use for the 3-way interaction with 3 groups taken into account?
So my question is whether it is possible to use an ANOVA for this comparison.
and which contrast would be usefull??
thanks in advance,
Marc van Ekeren
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