| % File src/library/datasets/man/sleep.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2012 R Core Team |
| % Copyright 1999-2012 The R Foundation |
| % Distributed under GPL 2 or later |
| |
| \name{sleep} |
| \docType{data} |
| \encoding{UTF-8} |
| \alias{sleep} |
| \title{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. |
| \tabular{rlll}{ |
| [, 1] \tab extra \tab numeric \tab increase in hours of sleep\cr |
| [, 2] \tab group \tab factor \tab drug given\cr |
| [, 3] \tab ID \tab factor \tab patient ID |
| } |
| } |
| \source{ |
| Cushny, A. R. and Peebles, A. R. (1905) |
| The action of optical isomers: II hyoscines. |
| \emph{The Journal of Physiology} \bold{32}, 501--510. |
| |
| Student (1908) |
| The probable error of the mean. |
| \emph{Biometrika}, \bold{6}, 20. |
| } |
| \details{ |
| The \code{group} variable name may be misleading about the data: |
| They represent measurements on 10 persons, not in groups. |
| %% But we keep it (as [,2]) for back compatibility. |
| } |
| \references{ |
| \enc{Scheffé}{Scheffe}, Henry (1959) |
| \emph{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)) |
| } |
| \keyword{datasets} |