Rohwer {heplots}R Documentation

Rohwer Data Set

Description

Data from an experiment by William D. Rohwer on kindergarten children designed to examine how well performance on a set of paired-associate (PA) tasks can predict performance on some measures of aptitude and achievement.

Usage

data(Rohwer)

Format

A data frame with 69 observations on the following 10 variables.

group
a numeric vector, corresponding to SES
SES
Socioeconomic status, a factor with levels Hi Lo
SAT
a numeric vector: score on a Student Achievement Test
PPVT
a numeric vector: score on the Peabody Picture Vocabulary Test
Raven
a numeric vector: score on the Raven Progressive Matrices Test
n
a numeric vector: performance on a 'named' PA task
s
a numeric vector: performance on a 'still' PA task
ns
a numeric vector: performance on a 'named still' PA task
na
a numeric vector: performance on a 'named action' PA task
ss
a numeric vector: performance on a 'sentence still' PA task

Details

The variables SAT, PPVT and Raven are responses to be potentially explained by performance on the paired-associate (PA) learning taskn, s, ns, na, and ss.

Source

Timm, N.H. 1975). Multivariate Analysis with Applications in Education and Psychology. Wadsworth (Brooks/Cole), Examples 4.3 (p. 281), 4.7 (p. 313), 4.13 (p. 344).

References

Friendly, M. (2007). HE plots for Multivariate General Linear Models. Journal of Computational and Graphical Statistics, 16, in press. http://www.math.yorku.ca/SCS/Papers/heplots.pdf

Examples

str(Rohwer)

# fit separate models for Lo/Hi SES
rohwer.ses1 <- lm(cbind(SAT, PPVT, Raven) ~ n + s + ns + na + ss, data=Rohwer, subset=SES=="Lo")

rohwer.ses2 <- lm(cbind(SAT, PPVT, Raven) ~ n + s + ns + na + ss, data=Rohwer, subset=SES=="Lo")

# ANCOVA, assuming equal slopes
rohwer.mod <- lm(cbind(SAT, PPVT, Raven) ~ SES + n + s + ns + na + ss, data=Rohwer)
Anova(rohwer.mod)

# Visualize the ANCOVA model
heplot(rohwer.mod)
# Add ellipse to test all 5 regressors
heplot(rohwer.mod, hypotheses=list("Regr" = c("n", "s", "ns", "na", "ss")))
# View all pairs
pairs(rohwer.mod, hypotheses=list("Regr" = c("n", "s", "ns", "na", "ss")))
# or 3D plot
 heplot3d(rohwer.mod, hypotheses=list("Regr" = c("n", "s", "ns", "na", "ss")))


[Package heplots version 0.8-4 Index]