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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Liz
October 16, 2008 05:02AM
Hi,

I'm new to using 3dLME, and am a little confused about the nomenclature of the contrast specifications used in model.txt.

I want to run a 3x3 analysis (2 factors with 3 levels each) and am using 3dLME rather than 3dANOVA because I have missing data. However, I don't understand how I can specify that I want the interaction of my factors to be analyzed- I could well have missed something but it seems that all of the examples posted on the forum just include simple contrasts to look at the main effects of the factors, but not the interactions between the factors.

Basically my task looks at processing visual stimuli, and I want to compare the effect of valence, of which there are 3 levels (positive, negative & neutral); and arousal, which also has 3 levels (low, medium & high); but my main hypothesis is that there will be a significant interaction between valence and arousal, however I'm not sure how to represent these contrasts!

Any suggestions would be really appreciated!
Thanks,
Liz :)

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Subject Author Posted

3dLME interaction effects

Liz October 16, 2008 05:02AM

Re: 3dLME interaction effects

Gang Chen October 16, 2008 09:25AM

Re: 3dLME interaction effects

Liz October 16, 2008 11:14AM