.\" -*- nroff -*- generated from .Rd format
.BG
.FN VarCorr
.TL
Extract variance and correlation components
.DN
This function calculates the estimated variances, standard
deviations, and correlations between the random-effects terms in a
linear mixed-effects model, of class `lme', or a nonlinear
mixed-effects model, of class `nlme'. The within-group error
variance and standard deviation are also calculated.
.CS
VarCorr(object, sigma, rdig)
.RA
.AG object
a fitted model object, usually an object inheriting from
class `lme'. 
.OA
.AG sigma
an optional numeric value used as a multiplier for the
standard deviations. Default is `1'.

.AG rdig
an optional integer value specifying the number of digits
used to represent correlation estimates. Default is `3'.

.RT
a matrix with the estimated variances, standard deviations, and
correlations for the random effects. The first two columns, named
`Variance' and `StdDev', give, respectively, the variance
and the standard deviations. If there are correlation components in
the random effects model, the third column, named `Corr',
and the remaining unnamed columns give the estimated correlations
among random effects within the same level of grouping. The
within-group error variance and standard deviation are included as
the last row in the matrix.


.EX
fm1 <- lme(distance ~ age, data = Orthodont, random = ~age)
VarCorr(fm1)
.KW models
.WR
