Hi Meng, the first row is what you want. The second row tests for an interaction between diagnosis, genotype, and age. doug

On 08/04/2012 10:23 PM, Meng Li wrote:

Hi Freesurfers,

My experimental design includes 3 discrete factors and 1 continuous variables:

Discrete factors: diagnosis with two levels (A, B); genotype with two levels (G, T); gender (F, M)

Continuous variable: age

So I can get 8 classes: AGF, AGM, ATF,ATM, BGF, BGM, BTF, BTM. Then I want to perform 2 (diagnosis)* 2(genotype) interaction analysis with regressing out the effect of gender and age. Is the following contrast matrix correct?

0.25 0.25 -0.25 -0.25 -0.25 -0.25 0.25 0.25 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 00.25 0.25 -0.25 -0.25 -0.25 -0.25 0.25 0.25

Any help will be very appreciated.

Best wishes,

Meng

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