afni.nimh.nih.gov

Yes, the second sentence looks good. We were just
dealing with a little language ambiguity here, I guess.

3dmaskave does not care how many clusters are in
the mask, or what their (non-zero) values are. Every
voxel is either in the input mask or not. And given
the mask, the program outputs the average data
value over that set of voxels.

- rick