The VarCorr
method returns a list of data.frame
s; one for
each distinct grouping factor. Each data.frame
has as many rows
as there are levels for that grouping factor and as many columns as
there are random effects for each level. For example a model can
contain a random intercept (one column) or a random
intercept and a random slope (two columns) for the same grouping
factor.
If conditional variances are requested, they are returned in the same
structure as the conditional modes (random effect
estimates/predictions).