contrMat

0th

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Contrast Matrices

Computes contrast matrices for several multiple comparison procedures.

Keywords
misc
Usage
contrMat(n, type=c("Dunnett", "Tukey", "Sequen", "AVE", 
                   "Changepoint", "Williams", "Marcus", 
                   "McDermott"), base = 1)
Arguments
n
a (possibly named) vector of sample sizes for each group or a vector of factor levels.
type
type of contrast.
base
an integer specifying which group is considered the baseline group for Dunnett contrasts.
Details

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

Value

  • The matrix of contrasts with appropriate row names is returned.

References

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

Aliases
  • contrMat
Examples
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")
Documentation reproduced from package multcomp, version 0.991-1, License: GPL

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