Extracting maximized profiled restricted log likelihood (PREML) from a varComp object
# S3 method for varComp
logLik(object, ...)A varComp object
Not used
A numeric value of class logLik.
The likelihood value is the profiled restricted log likelihood. The actual value depends on the residual contrast being chosen, but the location of maximum does not. Thus it is only comparable when the same residual contrast is used. This value is not to be compared to results reported using functions in other packages, e.g., nlme::lme or SAS. The degree of freedom reported is the number of variance components not on the boundary of parameter space, whereas the decision is based on object$control$boundary.eps.
Qu L, Guennel T, Marshall SL. (2013) Linear Score Tests for Variance Components in Linear Mixed Models and Applications to Genetic Association Studies. Biometrics, Volume 69, Issue 4, pages 883--892.
# NOT RUN {
library(nlme)
data(Oxide)
vcf = varComp(Thickness~Source, Oxide, ~Lot/Wafer)
logLik(vcf)
# }
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