PairedData (version 1.1.1)

levene.Var.test: Levene test of scale for paired samples

Description

Robust test of scale for paired samples based on absolute deviations from the trimmed means (or medians), called extended Brown-Forsythe test in Wilcox (1989).

Usage

levene.Var.test(x, ...)
# S3 method for default
levene.Var.test(x, y = NULL,
       alternative = c("two.sided", "less", "greater"),
       mu = 0,conf.level = 0.95,location=c("trim","median"),
tr=0.1, ...)

# S3 method for paired
levene.Var.test(x, ...)

Arguments

x

first sample or object of class paired.

y

second sample.

alternative

alternative hypothesis.

mu

the location parameter mu.

conf.level

confidence level.

location

location parameter for centering: trimmed mean or median.

tr

percentage of trimming.

…

further arguments to be passed to or from methods.

Value

A list with class "htest" containing the components of a paired t test.

Details

The data are transformed as deviations from the trimmed mean: X=abs(x-mean(x,tr=0.1)) and Y=(y-mean(y,tr=0.1)). A paired t test is then carried out on X and Y.

References

Wilcox, R.R. (1989) Comparing the variances of dependent groups. Psychometrika, 54, 305-315.

See Also

Var.test, grambsch.Var.test

Examples

# NOT RUN {
z<-rnorm(20)
x<-rnorm(20)+z
y<-(rnorm(20)+z)*2
levene.Var.test(x,y)

# Some variations
levene.Var.test(x,y,tr=0.2)
levene.Var.test(x,y,location="median")


data(anscombe2)
p<-with(anscombe2,paired(X2,Y2))
levene.Var.test(p)



# }