Description Usage Arguments Details Value References Examples

Computes contrast matrices for several multiple comparison procedures.

1 2 3 4 |

`n` |
a (possibly named) vector of sample sizes for each group. |

`type` |
type of contrast. |

`base` |
an integer specifying which group is considered the baseline group for Dunnett contrasts. |

Computes the requested matrix of contrasts for comparisons of mean levels.

The matrix of contrasts with appropriate row names is returned.

Frank Bretz, Torsten Hothorn and Peter Westfall (2010),
*Multiple Comparisons Using R*, CRC Press, Boca Raton.

Frank Bretz, Alan Genz and Ludwig A. Hothorn (2001), On the numerical
availability of multiple comparison procedures. *Biometrical Journal*,
**43**(5), 645–656.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
n <- c(10,20,30,40)
names(n) <- paste("group", 1:4, sep="")
contrMat(n) # Dunnett is default
contrMat(n, base = 2) # use second level as baseline
contrMat(n, type = "Tukey")
contrMat(n, type = "Sequen")
contrMat(n, type = "AVE")
contrMat(n, type = "Changepoint")
contrMat(n, type = "Williams")
contrMat(n, type = "Marcus")
contrMat(n, type = "McDermott")
### Umbrella-protected Williams contrasts, i.e. a sequence of
### Williams-type contrasts with groups of higher order
### stepwise omitted
contrMat(n, type = "UmbrellaWilliams")
### comparison of each group with grand mean of all groups
contrMat(n, type = "GrandMean")
``` |

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