06-17-2018 05:11 PM
I want to know if variable A influences the effect of variable B on variable C.
Would I use a saturated model or homogenous association (or something else entirely)? Clarification on the conceptual difference would be helpful! From what I understand, homogenous association is saying that B and C have a relationship and that relationship is identical at each level of A while the saturated model is saying that B and C have a relationship but that relationship does not have to be identical at each level of A? Thanks in advance for any help!!
06-18-2018 01:05 AM
yes, "model y= a|b|c" (see here https://blogs.sas.com/content/iml/2016/03/07/collection-effects-pairwise-interactions.html)
bear in mind, there's little statistical power for interaction effects; there'd have to be a specific interest in the Q. As you said, an interaction is an inconsistency of the strength of the effect across the levels of the other factor
06-20-2018 09:14 AM
"I want to know if variable A influences the effect of variable B on variable C."
As you've stated it, this suggests that C is the response and A and B are predictors. If so, then you simply want to test if the A*B interaction is significant in this model:
model c = a b a*b;