sleep {datasets} | R Documentation

## 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.

[, 1] | extra | numeric | increase in hours of sleep
[, 2] | group | factor | drug given
[, 3] | ID | factor | patient ID

### Details

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

### Source

Cushny, A. R. and Peebles, A. R. (1905) The action of optical isomers: II hyoscines. The Journal of Physiology 32, 501–510.

Student (1908) The probable error of the mean. Biometrika, 6, 20.

### References

Scheffé, Henry (1959) The Analysis of Variance. New York, NY: Wiley.

### 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))

[Package datasets version 3.3.2 Index]