Hello!
I?m fitting a model with glm(family binomial). The best model counts 9 Variables
and includes an interaction term that was generated by the product of to
continuous variables (a*b). All variables are correlated under a value of 0.7
(Spearman rank order) While the estimates of both main effects are negativ, the
resulting interaction term is positiv. This change of sign makes it difficult to
interpret the model and above all, is this perhaps due to a bad variable choice
?
Thanks a lot for helping
Christian
