R: McCulloch test of scale for paired samples

mcculloch.Var.test

R Documentation

McCulloch test of scale for paired samples

Description

Robust test of scale for paired samples based on spearman coefficient (the default, or kendall or pearson) of the transformed D=x-y and S=x+y.

Usage

mcculloch.Var.test(x, ...)

## Default S3 method:
mcculloch.Var.test(x, y = NULL,

alternative = c("two.sided", "less", "greater"),

method= c("spearman","pearson", "kendall"),

exact = NULL,conf.level = 0.95,continuity = FALSE, ...)

## S3 method for class 'paired'
mcculloch.Var.test(x, ...)

Arguments

`x`	first sample or object of class paired.
`y`	second sample.
`alternative`	alternative hypothesis.
`method`	a character string indicating which correlation coefficient is to be used for the test. One of "spearman", "kendall", or "pearson", can be abbreviated.
`exact`	a logical indicating whether an exact p-value should be computed.
`conf.level`	confidence level.
`continuity`	logical: if true, a continuity correction is used for Spearman's rho when not computed exactly.
`...`	further arguments to be passed to or from methods.

Value

A list with class "htest" containing the components of a (Spearman) correlation test.

Author(s)

Stephane CHAMPELY

References

McCulloch, C.E. (1987) Tests for equality of variances for paired data. Communications in Statistics - Theory and Methods, 16, 1377-1391.

Examples

z<-rnorm(20)
x<-rnorm(20)+z
y<-(rnorm(20)+z)*2
mcculloch.Var.test(x,y)

p<-paired(x,y)
mcculloch.Var.test(p)

# A variation with kendall tau
mcculloch.Var.test(p,method="kendall")

# equivalence with the PitmanMorgan test
mcculloch.Var.test(p,method="pearson")
Var.test(p)