AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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gang
April 02, 2013 05:30PM
> Can anyone please tell me where to find out what the contrast options mean, such as tau^2 and QE?

tau^2 is the cross-subjects variance and measures the heterogeneity of the group, and QE is the chi-square test that indicates whether the cross-subjects variance is significant at a brain region.

If you run the analysis with the assumption of different variance across the groups (with option -unequal_variance) in 3dMEMA, I believe that 3dMEMA also provides the ratio of the within-group variances that shows whether the two groups have different variability (heteroskedasticity) in a region.

Gang
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3dMEMA output

katya.dobryak April 02, 2013 04:22PM

Re: 3dMEMA output

gang April 02, 2013 05:30PM