Restricted maximum likelihood

Restricted Maximum Likelihood (REML) is a statistical technique used primarily in the estimation of variance components in mixed models. It is particularly useful in the context of linear mixed-effects models, where researchers are interested in both fixed effects and random effects. ### Key Features of REML: 1. **Variance Component Estimation**: REML is mainly used to estimate variance components associated with random effects. This is important when distinguishing between the effects of different sources of variability in the data.