Central to the idea of variance components models is the idea of fixed and random effects. Each effect in a variance components model must be classified as either a fixed or a random effect. Fixed ...

The MODEL statement names a single dependent variable and the fixed effects, which determine the X matrix of the mixed model (see the "Parameterization of Mixed Models" section for details). The ...

Mixed-effects location scale models represent a powerful statistical framework designed to investigate longitudinal data. By simultaneously modelling the mean trajectories (location) and residual ...