nlschools {MASS} | R Documentation

## 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)
    summary(nl.lme)

[Package MASS version 7.3-45 Index]