3dMVM with continuous variable (between-subject factor of interest)

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1

Dear AFNI expert,

Hi,
My question is,

I finished the analysis with 3dMVM; however, I started to doubt whether using 3dMVM is correct in my case.

When I have a continuous between-subject variable of interest (not covariate of non-interest), can I use 3dMVM?

Specifically,
I have 2 categorical within-subject factors
2 continuous between-subject factors of interest
and 1 between-subject covariate of non-interest.

I want to examine 4 way, 3way, 2way, and main effect.

In this case (when I have continuous variable of interests), can I use 3dMVM? or… I need to use 3dLME?
I guess that 3dMVM (test of ANOVA, ANCOVA) would assume variables of interest as a categorical variable.

Thank you very much,
Irene

2

Irene,

From the modeling perspective, what really matters is the nature of each variable: quantitative vs categorical, between- vs within-subject? The model/program does not care a bit as to whether you are interested in each variable. So, 3dMVM is just fine for your model and data structure. And so are 3dLME and 3dLMEr.

3

I see,
Thank you so much for reply!

Best,
Leehyun