Hi Heidi - It's up to you. As long as the N of subjects at each point is included in the statistical test, this will adjust the corresponding p-value accordingly.

Best, a.y

________________________________ From: freesurfer-bounces@nmr.mgh.harvard.edu [freesurfer-bounces@nmr.mgh.harvard.edu] on behalf of Jacobs H (NP) [h.jacobs@maastrichtuniversity.nl] Sent: Friday, March 10, 2017 5:39 PM To: Freesurfer support list Subject: [Freesurfer] Repost: tracula stats including NAs?

Hi FreeSurfer,

I have analyzed my diffusion data using Tracula and combined the voxelwise diffusion measures across all subjects in one file (following the guidelines on the wiki). In this text file, I saw that for some of these voxels some people have NAs, so their tract is most likely shorter. I now would like to do t-tests for each voxel and plot these in freeview (as also suggested in the wiki).

Would you recommend to only take those voxels that have a value in each subject to keep the number of subjects consistent at each voxel ?

Look forward to your thoughts on this.

Best wishes Heidi