VarCorr: Extract Variance and Correlation Components
Description
This function calculates the estimated variances,
standard deviations, and correlations between the
random-effects terms in a mixed-effects model, of class
merMod (linear, generalized or
nonlinear). The within-group error variance and standard
deviation are also calculated.
Usage
## S3 method for class 'merMod':
VarCorr(x, sigma, rdig)
Arguments
x
a fitted model object, usually an object inheriting from
class merMod.
sigma
an optional numeric value used as a multiplier for the
standard deviations. Default is 1.
rdig
an optional integer value specifying the number of digits
used to represent correlation estimates. Default is 3.
Value
a list of matrices, one for each random effects grouping
term. For each grouping term, the standard deviations and
correlation matrices for each grouping term are stored as
attributes "stddev" and "correlation",
respectively, of the variance-covariance matrix, and the
residual standard deviation is stored as attribute
"sc" (for glmer fits, this attribute stores
the scale parameter of the model).