Using a class variable, it is like intercepts, the fixed effect will give you the effect for the average subject while the combination of the fixed and random will give you the value for that particular subject. This is assuming you are specifying the random statement per subject. It might be easier to give you an interpretation if I can see your model. Be aware that sometimes when specifying fixed and random effects and depending on the level of detail of the data, the random effect might be zero, because they are acting as residuals. regards, Rita
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