# NOT RUN {
nl1 <- within(nlschools, {
IQave <- tapply(IQ, class, mean)[as.character(class)]
IQ <- IQ - IQave
})
cen <- c("IQ", "IQave", "SES")
nl1[cen] <- scale(nl1[cen], center = TRUE, scale = FALSE)
nl.lme <- nlme::lme(lang ~ IQ*COMB + IQave + SES,
random = ~ IQ | class, data = nl1)
summary(nl.lme)
# }
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