Eighth-Grade Pupils in the Netherlands

Description

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.

Usage

data(nlschools)

Format

This data frame contains 2287 rows and the following columns:

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.

References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

Examples

library(nlme)
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 = TRUE, scale = FALSE)

nl.lme <- lme(lang ~ IQ*COMB + IQave + SES,
              random = ~ IQ | class, data = nl1)
summary(nl.lme)