boxM {biotools} | R Documentation |

## Box's M-test

### Description

It performs the Box's M-test for homogeneity of covariance matrices obtained from multivariate normal data according to one classification factor. The test is based on the chi-square approximation.

### Usage

```
boxM(data, grouping)
```

### Arguments

`data` |
a numeric data.frame or matrix containing |

`grouping` |
a vector of length n containing the class of each observation; it is usualy a factor. |

### Value

A list with class "htest" containing the following components:

`statistic` |
an approximated value of the chi-square distribution. |

`parameter` |
the degrees of freedom related of the test statistic in this case that it follows a Chi-square distribution. |

`p.value` |
the p-value of the test. |

`cov` |
a list containing the within covariance matrix for each level of |

`pooled` |
the pooled covariance matrix. |

`logDet` |
a vector containing the natural logarithm of each matrix in |

`data.name` |
a character string giving the names of the data. |

`method` |
the character string "Box's M-test for Homogeneity of Covariance Matrices". |

### Author(s)

Anderson Rodrigo da Silva <anderson.agro@hotmail.com>

### References

Morrison, D.F. (1976) *Multivariate Statistical Methods*.

### Examples

```
data(iris)
boxM(iris[, -5], iris[, 5])
# End (not run)
```

*biotools*version 4.2 Index]