Hi,
I am trying to examine the moderating effects on a curvilinear relation between variable A and B in a multiple regression,
ie.
A ->B : positive coeff.
A^2 ->B : negative coefficient
I want to examine whether introducing variable C shifts the whole distribution of A to the right.
Variable A and B are continuous
Variable C is categorical.
For examing such a moderating role of variable C, I think that only the interaction of AxC has to be significant and positive - is that right?
Or does the interaction betwen A^2 xC also has to be significant (in that case, this would imply that the distribution of A is not only shifted to the right, but also that the shape of the distribution has changed, correct?)
Any advice is appreciated.
Thanks,
Pat
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