pub fn nlschools() -> Result<DataFrame, PolarsError>Expand description
§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:
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:
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)
## IGNORE_RDIFF_BEGIN
summary(nl.lme)
## IGNORE_RDIFF_END