swh:1:snp:813359ba77493c9d5dd1abad9a1f53490a8abf57
Tip revision: b7346fb4a36014a61289b3e1ec88cc08bb794cae authored by Torsten Hothorn on 28 August 2019, 10:50:06 UTC
version 1.3-1
version 1.3-1
Tip revision: b7346fb
rotarod.Rd
\name{rotarod}
\docType{data}
\alias{rotarod}
\title{Rotating Rats}
\description{
The endurance time of 24 rats in two groups on a rotating cylinder.
}
\usage{rotarod}
\format{
A data frame with 24 observations on 2 variables.
\describe{
\item{\code{time}}{
endurance time (seconds).
}
\item{\code{group}}{
a factor with levels \code{"control"} and \code{"treatment"}.
}
}
}
\details{
The rats were randomly assigned to receive a fixed oral dose of a centrally
acting muscle relaxant (\code{"treatment"}) or a saline solvent
(\code{"control"}). The animals were placed on a rotating cylinder and the
endurance time of each rat, i.e., the length of time each rat remained on the
cylinder, was measured up to a maximum of 300 seconds.
This dataset is the basis of a comparison of 11 different software
implementations of the Wilcoxon-Mann-Whitney test presented in Bergmann,
Ludbrook and Spooren (2000).
}
\note{
The empirical variance in the control group is 0 and the group medians are
identical. The exact conditional \eqn{p}-values are 0.0373 (two-sided) and
0.0186 (one-sided). The asymptotic two-sided \eqn{p}-value (corrected for
ties) is 0.0147.
}
\source{
Bergmann, R., Ludbrook, J. and Spooren, W. P. J. M. (2000). Different
outcomes of the Wilcoxon-Mann-Whitney test from different statistics packages.
\emph{The American Statistician} \bold{54}(1), 72--77.
\doi{10.1080/00031305.2000.10474513}
}
\examples{
## One-sided exact Wilcoxon-Mann-Whitney test (p = 0.0186)
wilcox_test(time ~ group, data = rotarod, distribution = "exact",
alternative = "greater")
## Two-sided exact Wilcoxon-Mann-Whitney test (p = 0.0373)
wilcox_test(time ~ group, data = rotarod, distribution = "exact")
## Two-sided asymptotic Wilcoxon-Mann-Whitney test (p = 0.0147)
wilcox_test(time ~ group, data = rotarod)
}
\keyword{datasets}