nlschools {MASS} | R Documentation |
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.
nlschools
This data frame contains 2287 rows and the following columns:
lang
IQ
class
GS
COMB
, and some may have been omitted with missing
values).
SES
COMB
0/1
)? Classes which
contained pupils from grades 7 and 8 are coded 1
, but only
eighth-graders were tested.
Snijders, T. A. B. and Bosker, R. J. (1999) Multilevel Analysis. An Introduction to Basic and Advanced Multilevel Modelling. London: Sage.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
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)