Eighth-Grade Pupils in the Netherlands

SUMMARY:

Snijders and Bosker (1999) use as a running example a study of 2287 eighth-grade pupils (aged about 11) in 132 classes in 131 schools in the Netherlands. Only the variables used in our examples are supplied.

DATA DESCRIPTION:

This data frame contains 2287 rows and the following columns:

ARGUMENTS:

lang
language test score
IQ
Verbal IQ
class
class ID
GS
Class size: number of eighth-grade pupils recorded in the class (there may be others: see COMB, and some may have been omitted with missing values).
SES
Social-economic status of pupil's family.
COMB
were the pupils taught in a multi-grade class ( 0/1)? Classes which contained pupils from grades 7 and 8 are coded 1, but only eighth-graders were tested.

SOURCE:

Snijders, T. A. B. and Bosker, R. J. (1999) Multilevel Analysis. An Introduction to Basic and Advanced Multilevel Modelling. London: Sage.

EXAMPLES:

nl1 <- nlschools
attach(nl1)
classMeans <- tapply(IQ, class, mean)
nl1$IQave <- classMeans[as.character(class)]
nl1$IQ <- nl1$IQ - nl1$IQave
detach()
cen <- c("IQ", "IQave", "SES")
nl1[cen] <- scale(nl1[cen], center = T, scale = F)
options(contrasts = c("contr.treatment", "contr.poly"))
nl.lme <- lme(lang ~ IQ*COMB + IQave + SES,
              random = ~ IQ | class, data = nl1)
summary(nl.lme)