Dear Gang,
We have now carried out the 3dMEMA steps correctly after the suggestion by Isaac (see post below) that the syntax of our code had a problem. We find that with 3dMEMA we obtain 3 clusters, whereas with 3dRegAna on the same subjects we get 18 clusters. The three clusters from 3dMEMA overlap with three of the 18 clusters from 3dRegAna.
I wonder if testing for a linear test using a conjunction of 2 t-tests is a more strict test than testing for a linear trend in 3dRegAna? For example, is the 3dMEMA conjunction analysis method only identifying the largest linear increases, whereas the 3dRegAna method has a less strict criterion?
Christine