Thank you so much!

Okie doke.

So then, for an interaction between gender x handedness x ROIsInteractionTerm (continuous), controlling for eTIV, the contrast would be the following?

[ 0 0 0 0 0.5 -0.5 -0.5 0.5 0 0 0 0]

All the best,

Fred

On Apr 28, 2023, at 10:30 AM, Douglas N. Greve <dgreve@mgh.harvard.edu> wrote:

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The method you describe is only for discrete variables, not continuous ones. The traditional method for continuous variables is to create a new variable where you multiply them together. You should normalize you continuous variables too (ie, subtract the mean and divide by the stddev).

On 4/24/2023 8:52 PM, Fred d'Oleire Uquillas wrote:
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Dear Fs support,

If I have the following FSGD with 4 classes and 3 variables, and I'd like to run an interaction of ROIa x ROIb controlling for the third covariate (eTIV), would I use the following contrast?

[0 0 0 0 0.25 -0.25 -0.25 0.25 0.25 -0.25 -0.25 0.25 0 0 0 0]

For the interaction of ROIa x ROIb x class + eTIV.

Thank you so much in advance for your help!

All the best,

Fred
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