Last data update: 2014.03.03

R: Permutational Bartlett's test of homogeneity of variances
perm.bartlett.testR Documentation

Permutational Bartlett's test of homogeneity of variances

Description

Performs a permutational Bartlett's test of homogeneity of k variances.

Usage

perm.bartlett.test(formula, data, nperm = 999)

Arguments

formula

a formula of the form a ~ b where a gives the data values and b the corresponding groups.

data

an optional data frame containing the variables in the formula formula. By default the variables are taken from environment(formula).

nperm

number of permutations.

Details

The function deals with the limitted floating point precision, which can bias calculation of p-values based on a discrete test statistic distribution.

Value

method

name of the test.

data.name

a character string giving the name(s) of the data.

statistic

test statistics of the parametric test.

permutations

number of permutations.

p.value

p-value of the permutational test.

Author(s)

Maxime Herv<c3><a9> <mx.herve@gmail.com>

See Also

bartlett.test

Examples

response <- c(rnorm(12),rpois(12,1),rnorm(12,2,1))
fact <- gl(3,12,labels=LETTERS[1:3])
perm.bartlett.test(response~fact)

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(RVAideMemoire)
*** Package RVAideMemoire v 0.9-56 ***
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/RVAideMemoire/perm.bartlett.test.Rd_%03d_medium.png", width=480, height=480)
> ### Name: perm.bartlett.test
> ### Title: Permutational Bartlett's test of homogeneity of variances
> ### Aliases: perm.bartlett.test
> 
> ### ** Examples
> 
> response <- c(rnorm(12),rpois(12,1),rnorm(12,2,1))
> fact <- gl(3,12,labels=LETTERS[1:3])
> perm.bartlett.test(response~fact)
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	Permutational Bartlett test of homogeneity of variances

data:  response by fact
999 permutations
Bartlett's K-squared = 3.3047, p-value = 0.149

> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>