> I have to put the p at 2.2X10-5

I've seen such a scenario several times myself, and I have to say that what you see is what you have. It basically means those regions are consistently correlated with the seed among the subjects, which is the opposite of what people face most of the time (lack of power) . I don't have a solution as to how to handle the situation from the statistical perspective.

> and again alot of it is a ring on the outer edge of the brain

It could be head motion or something else, but you'd have to do some detection work to sort it out.

> but my 2 sample ttest looks reasonable.

My guess is that the group comparison (subtraction) cancels out most of the effect including the ring effect.

Gang



Edited 1 time(s). Last edit at 10/14/2014 04:39PM by Gang.