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
May 23, 2012 04:53PM
A couple of comments:

1) Covariate centering. You need to center your covariate and, better yet, scale by the standard deviation. Do your groups have roughly the same average about the covariate? If they are significantly different from each other, when you test about group difference in terms of HDR, what kind of hypothesis about the covariate value: at the overal mean of the covariate across groups, or in regard to each group's own center/mean?

2) Do you assume the groups have roughly the same covariate effect? If unknown, you may consider model each group with different slope:

Model:-1+Time:Group+Group:MyCov

Also change to

SS:marginal

Gang
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Subject Author Posted

Comparing IRFs Between Groups

John Graner May 23, 2012 09:54AM

Re: Comparing IRFs Between Groups

gang May 23, 2012 02:19PM

Re: Comparing IRFs Between Groups

John Graner May 23, 2012 04:08PM

Re: Comparing IRFs Between Groups

gang May 23, 2012 04:53PM

Re: Comparing IRFs Between Groups

John May 24, 2012 10:37AM

Re: Comparing IRFs Between Groups

gang May 24, 2012 02:09PM

Re: Comparing IRFs Between Groups

John May 24, 2012 02:45PM