Hello,

I have a general question about how to interpret regression coefficients, when you have more than one interaction term.

I am aware that with one interaction term (between the independent variables X and Z), the coefficient of X should be interpreted as the effect of X on Y, when Z=0. To find the effect of X on Y when Z=1, I would add the coefficients of X and X#Z.

I suppose that if if I have two interaction terms (X#Z and X#W), the coefficient of X should be interpreted as the effect of X on Y, when Z=0 and W=0. But I am not sure how to interpret the coefficient of the interaction terms. Should the coefficient of X#Z be interpreted as the interaction effect when W=0 or does the inclusion of X#W not change how to interpret X#Z? And what does it mean if the coefficient of X#Z is significant or not?

Best regards,
Magnus Jensen