Hi I just wanted to check that we are doing the correct thing here...
We scanned an initial group of subjects on an fMRI task and we realised that
there was a problem with the aquisition sequence. So, we scanned a new
group of subjects again, a few months later. Of course, we wanted to see if
we could still use the original subjects. Our strategy was as follows:
Place all the lower level feats into a higher-level analysis as two groups, in
two columns as outlined in the Feat manual. [# #]. Then check for
differences between the groups [1 -1] and [-1 1] on each contrast. Since
there were no major differences, but still thinking it is safer treat these groups
as having different variances, we then wanted to know the COPE for both
groups combined. So, we simply set the higher level contrast as [1 1].
Does this sound about right?
Cheers,
Dan CM
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