> No individual fixed effect of diagnosis is included in the specified LMM-1 model but it yields z and p-values for the fixed effects?
> Two-way interactions are not specified in the model?
The R notation for the model formulation
Diagnosis *Age* Sex
is equivalent to
Diagnosis + Age + Sex + Diagnosis:Age + Diagnosis:Sex + Age:Sex + Diagnosis:Age:Sex
In other words, all the main effects, two-way and three-way interactions among the three variables (Diagnosis, Age, and Sex) are included in the model.
Gang