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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Liu Mengxing
February 16, 2021 09:55AM
Hi,

I have one statistic question:
Say I have a within-subject repeated measure design, with two conditions A and V, I want to test if there are any regions more involved in A comparing to it in V.

Two approaches in my mind:
1) each condition has one regressor in the first level GLM matrix, resulting in beta for A and beta for V, for group level analysis, do paired t-test to test the difference of beta-A against beta-V. (i.e. the example script s5.ttest.paired in AFNI_data6/group_results)

2) add a -gltsym 'SYM: A -V' -glt_label 1 A-V, to test the difference of A against B at subject level, resulting one beta indicating the difference, then do one-sample t-test to test this difference beta value against zero.

Could you share your mind on this topic, which approach is more recommended, or it depends on different conditions?

Many thanks!

best,
Meng
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Subject Author Posted

condition contrast at first level or second level?

Liu Mengxing February 16, 2021 09:55AM

Re: condition contrast at first level or second level?

gang February 16, 2021 03:23PM