Hi, I'm new to GLMMs and want to check that I have used the appropriate syntax for my analyses. I'm analysing a longitudinal study looking at children's ('subject') behaviours ('beh') towards eleven different stimuli ('stimulus') at four different timepoints ('time'). Time and stimulus are repeated measures variables as all children were exposed to all stimuli at all timepoints. I'm testing against a Poisson distribution because the behavioural data are counts (and there is no overdispersion). My basic syntax looks like this: proc glimmix data=data method=laplace ic=q; class subject stimulus; model beh = stimulus time stimulus*time / s dist=Poisson; random int / subject=subject; random stimulus / subject=subject; random time / type=AR(1) subject=subject; nloptions tech=quanew; run; I'm testing these full models against nested models with fewer fixed effects (stimulus & time without the interaction, stimulus only, time only, and a null model with no fixed effects) and selecting models on the basis of their AIC values. Are these analyses appropriate for my data? Many thanks.
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