Student's Sleep Data

Description

Data which show the effect of two soporific drugs (increase in hours of sleep compared to control) on 10 patients.

Usage

sleep

Format

A data frame with 20 observations on 3 variables.

Details

The group variable name may be misleading about the data: They represent measurements on 10 persons, not in groups.

Source

⁠Cushny and Peebles (1905); ⁠Student (1908).

References

⁠Cushny AR, Peebles AR (1905). “The Action of Optical Isomers: II. Hyoscines.” The Journal of Physiology, 32(5–6), 501–510. doi:10.1113/jphysiol.1905.sp001097.

⁠Scheffé H (1959). The Analysis of Variance. John Wiley & Sons. ISBN 978-0471758341.

⁠Student (1908). “The Probable Error of a Mean.” Biometrika, 6(1), 1. doi:10.2307/2331554.

Examples

require(stats)
## Student's paired t-test
with(sleep,
     t.test(extra[group == 1],
            extra[group == 2], paired = TRUE))

## The sleep *prolongations*
sleep1 <- with(sleep, extra[group == 2] - extra[group == 1])
summary(sleep1)
stripchart(sleep1, method = "stack", xlab = "hours",
           main = "Sleep prolongation (n = 10)")
boxplot(sleep1, horizontal = TRUE, add = TRUE,
        at = .6, pars = list(boxwex = 0.5, staplewex = 0.25))