Is that your design matrix or the contrast matrix? To test for the interaction between two continuous variables, one usually creates a new variable by multiplying them together and then just testing for the regressor for that variable being different than zero

On 08/23/2017 12:34 PM, Timothy Hendrickson wrote:

Freesurfer experts,

I have created a design matrix in order to test for whether there is an interaction effect between two continuous co-variates controlling for a categorical variable.

So I have one categorical variable with two levels, and two continuous co-variates.

My design matrix is as follows:

0 0 1 1 0 0 0 0 0 0 1 1

Is this correct?

-Tim

Timothy Hendrickson Department of Psychiatry University of Minnesota Bioinformatics and Computational Biology M.S. Candidate Office: 612-624-6441 Mobile: 507-259-3434 (texts okay)

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