Re: [Freesurfer] mean cortical thickness not equal to averaged ROIs cortical thickness

Hi Nabin

unless the areas are the same size, the mean of the areal means won't equal the overall mean.

cheers Bruce On Sat, 25 Jun 2016, Nabin Koirala wrote:

Hi freesurfer team,  I extracted the cortical thickness values using aparcstats2table command and I got the cortical thickness values for 34 regions and mean cortical thickness for each hemisphere. But when I averaged the cortical thickness from those 34 regions regions it was different than the mean cortical thickness obtained by aparcstats2table. I would expect it to be the same or very close but I checked it for more than 100 subjects and they are significantly different. Am I missing something silly here ?

Thank you.

Regards,  Nabin