rotarod {exactRankTests} | R Documentation |

## Rotating Rats Data

### Description

The endurance time of 24 rats in two groups in a rotating cylinder.

### Usage

data(rotarod)

### Format

A data frame with 24 observations on the following 2 variables.

- time
the endurance time

- group
a factor with levels `control`

and `treatment`

.

### Details

The 24 rats received a fixed oral dose of a centrally acting muscle relaxant
(treatment) or a saline solvent (control). They were placed on a rotating
cylinder and the length of time each rat remains on the cylinder is
measured, up to a maximum of 300 seconds.
The rats were randomly assigned to the control and treatment group.

Note that the empirical variance in the control group is 0 and that the
group medians are identical.

This dataset serves as the basis of an comparision of the results of the
Wilcoxon-Mann-Whitney test computed by 11 statistical packages in Bergmann
et al. (2000). The exact conditional p-value is $0.0373$ (two-sided) and
$0.0186$ (one-sided). The asymptotic two-sided
p-value (corrected for ties) is reported as $0.0147$.

### Source

Reinhard Bergmann, John Ludbrook & Will P.J.M. Spooren (2000),
Different outcomes of the Wilcoxon-Mann-Whitney test from different
statistics packages. *The American Statistician*,
**54**(1), 72–77.

### Examples

data(rotarod)
wilcox.exact(time ~ group, data=rotarod, alternative="g")
wilcox.exact(time ~ group, data=rotarod, conf.int=TRUE)
wilcox.exact(time ~ group, data=rotarod, exact=FALSE)
# the permutation test
perm.test(time ~ group, data=rotarod)
perm.test(time ~ group, data=rotarod, exact=FALSE)

[Package

*exactRankTests* version 0.8-30

Index]