Rohwer {heplots} | R Documentation |
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.
data(Rohwer)
A data frame with 69 observations on the following 10 variables.
group
SES
Hi
Lo
SAT
PPVT
Raven
n
s
ns
na
ss
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
.
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).
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
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")))