Mathematical assessment scores for 36 students enrolled in a biostatistics course according to whether or not the students had successfully completed a calculus course prior to enrolling in the biostatistics course
CALCULUS
A data frame with 36 observations on the following 2 variables:
score
(assessment score for each student)
calculus
(a factor with levels NO
and YES
for students who did not and did successfully complete calculus prior to enrolling in the biostatistics course)
Ugarte, M. D., Militino, A. F., and Arnholt, A. T. 2015. Probability and Statistics with R, Second Edition. Chapman & Hall / CRC.
# ggplot2 approach
ggplot(data = CALCULUS, aes(sample = score)) + stat_qq() + facet_grid(. ~ calculus)
ggplot(data = CALCULUS, aes(x = calculus, y = score, fill = calculus)) + geom_boxplot() +
guides(fill = "none") + scale_fill_brewer()
ggplot(data = CALCULUS, aes(sample = score, color = calculus)) + stat_qq()
# lattice approach
qqmath(~score|calculus, data = CALCULUS)
qqmath(~score, group = calculus, type = c('p', 'r'), auto.key=TRUE, data = CALCULUS)