# NOT RUN {
if(requireNamespace("lme4") && requireNamespace("RLRsim")){
data(Hofmann)
library("lme4")
# Random-Intercepts Model
lmmHofmann0 = lmer(helping ~ (1|id), data = Hofmann)
vy_Hofmann = var(Hofmann[,'helping'])
# Computing icca
VarCorr(lmmHofmann0)$id[1,1]/vy_Hofmann
# Estimating Group-Mean Centered Random Slopes Model, no level 2 variables
lmmHofmann1 <- lmer(helping ~ mood_grp_cent + (mood_grp_cent |id),
data = Hofmann, REML = FALSE)
X_Hofmann = model.matrix(lmmHofmann1)
P = ncol(X_Hofmann)
T1_Hofmann = VarCorr(lmmHofmann1)$id[1:P,1:P]
# Computing iccb
icc_beta(X_Hofmann, Hofmann[,'id'], T1_Hofmann, vy_Hofmann)$rho_beta
# Performing LR test
# Need to install 'RLRsim' package
library("RLRsim")
lmmHofmann1a <- lmer(helping ~ mood_grp_cent + (1 | id),
data = Hofmann, REML = FALSE)
obs.LRT <- 2*(logLik(lmmHofmann1) - logLik(lmmHofmann1a))[1]
X <- getME(lmmHofmann1,"X")
Z <- t(as.matrix(getME(lmmHofmann1,"Zt")))
sim.LRT <- LRTSim(X, Z, 0, diag(ncol(Z)))
(pval <- mean(sim.LRT > obs.LRT))
} else {
stop("Please install packages `RLRsim` and `lme4` to run the above example.")
}
# }
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