Hi,
I just completed a mixed effects OLS analysis for the group mean of 18 first-
level FEAT directory inputs. When I looked at the output, the higher-level
COPE map was empty. I'm not sure what this means. There was a MaxZStat
of 2.6, but no blobs of activation are visible on the map (presumably because
so few voxels passed threshold). I'm puzzled about this because (a) most of
the lower level COPES do show activation (b) I did not apply any masks to the
data (c) my supervisor predicted that we'd see tons of activation :)
I understand that this result may simply reflect the statistics that were
applied at the higher-level (e.g. different degrees of freedom). But, I'm also
concerned that something might have gone wrong with the analysis.
Any thoughts on this?
Thanks,
Mona
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