Dear SPM experts,
I have two groups and two acquisitions for each subject (before and after treatment). I am not sure what design matrices and contrasts I have to use.
I have thought that I can use the two first column of the matrix for modeling the groups, the next two the time of acquisition and the next for modeling the subjects.
I don't know what contrasts I have to use to study all the group and time effects and the interaction between them or simply if that design matrix is enough for the analysis.
Any suggestion?
Thanks a lot,
Alex
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