\Header{sleep}{Students' Sleep Data}
\keyword{datasets}{sleep}
\begin{Description}\relax
Data which show the effect of two soporific drugs (increase in hours
of sleep) on groups consisting of 10 patients each.\end{Description}
\begin{Usage}
\begin{verbatim}data(sleep)\end{verbatim}
\end{Usage}
\begin{Format}\relax
A data frame with 20 observations on 2 variables.
\Tabular{rlll}{
[, 1] & extra & numeric & increase in hours of sleep\\{}
[, 2] & group & factor  & patient group
}\end{Format}
\begin{Source}\relax
Student (1908)
The probable error of the mean.
\emph{Biometrika}, \bold{6}, 20.\end{Source}
\begin{References}\relax
Scheffé, Henry (1959)
\emph{The Analysis of Variance.}
New York, NY: Wiley.\end{References}
\begin{Examples}
\begin{ExampleCode}
data(sleep)
## ANOVA
anova(lm(extra ~ group, data = sleep))
\end{ExampleCode}
\end{Examples}

