I am going through a model selection process with a mixed-model with 3 variables: A, B, and C. B and C are orthogonal factors. B or C may interact with A, so my full model would be:
Y ~ A + B + C + A*B + A*C
When I run my analysis, I get four models sharing the lowest AICc.
Y ~ B + A*C Y ~ A + B + A*C Y ~ B + C + A*C Y ~ A + B + C + A*C
I am very confused about what is going on. Obviously there is an interaction between A and C, but how can they all have the same AICc value? Where do I go from here in model selection?