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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jill
September 21, 2007 05:22PM
hi kids,
I've been thinking about an analysis and i'm not sure how to go about it...

Imagine you have a blocked-design experiment with 3 conditions: A, B, & C. You do multiple regression for each individual subject. C is your baseline, so there are regressors for A & B in the model, but not for C. Thus, there is no beta weight for C. How would you go about doing a group mixed effects analysis to see where in the group A differs from C?

3dttest: you can't compare the means of A & C since there's no beta for C. how inappropriate would it be to compare the mean of A to zero without accounting for the variance of B?

3dAnova: if you wanted to do an ANOVA on beta weights, how is the variance attributable to C accounted for without a beta weight for C? what would a contrast where A = 1 and B = 0 mean?

thanks for your thoughts,
jill
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Subject Author Posted

group analysis

jill September 21, 2007 05:22PM

Re: group analysis

Gang Chen September 21, 2007 05:33PM

Re: group analysis

jill September 21, 2007 05:41PM

Re: group analysis

Gang Chen September 21, 2007 05:46PM

Re: group analysis

jill September 21, 2007 06:15PM