Hi all,

Thanks in advance for taking the time to answer my question. I'd like to test the interaction between two variables:

Var 1: is dichotomous (1=gene present or 0=gene not present)
Var 2: continuous variable

I'd like to look at a Var1*Var2 interaction, which I have done previously with two continuous variables but not with dichotomous ones. If I multiply Var1 and Var2 the 0s would negate the effect. I was thinking of changing the dichotomisation to 1 and 2 instead or 1 -1 but I am not sure if this would be the correct way to proceed.

Any input would be highly appreciated. Thanks!!