hovBF: Homogeneity of Variance: Brown-Forsyth method

Description Usage Arguments Value Author(s) References Examples

View source: R/hovBF.R

Description

Homogeneity of Variance: Brown–Forsyth method

Usage

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hovBF(x, data=NULL, ..., na.rm = TRUE)
hovplotBF(x, data, ..., na.rm = TRUE,
          main = "Brown-Forsyth Homogeneity of Variance", plotmath = TRUE)

Arguments

x

Model formula with one response variable and one factor.

data

data.frame

...

Other arguments. hovplotBF sends them on to the panel function. hovBF ignores them.

na.rm

A logical value indicating whether 'NA' values should be stripped before the computation proceeds. See median.

main

main title for the plot.

plotmath

Logical. When TRUE (the default) the strip labels use plotmath. When FALSE the strip labels use ASCII.

Value

hovplotBF returns a three-panel trellis object. hovBF returns an htest object.

Author(s)

Richard M. Heiberger <rmh@temple.edu>

References

Brown, M.~B. and Forsyth, A.~B. (1974). “Robust tests for equality of variances.” Journal of the American Statistical Association, 69:364–367.

Examples

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data(batch)
batch1.aov <- aov(Calcium ~ Batch, data=batch)
anova(batch1.aov)
hovBF(Calcium ~ Batch, data=batch)
hovplotBF(Calcium ~ Batch, data=batch)

Example output

Loading required package: lattice
Loading required package: grid
Loading required package: latticeExtra
Loading required package: RColorBrewer
Loading required package: multcomp
Loading required package: mvtnorm
Loading required package: survival
Loading required package: TH.data
Loading required package: MASS

Attaching package: 'TH.data'

The following object is masked from 'package:MASS':

    geyser

Loading required package: gridExtra
Analysis of Variance Table

Response: Calcium
          Df   Sum Sq  Mean Sq F value   Pr(>F)   
Batch      4 0.096976 0.024244  5.5352 0.003626 **
Residuals 20 0.087600 0.004380                    
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

	hov: Brown-Forsyth

data:  Calcium
F = 0.032193, df:Batch = 4, df:Residuals = 20, p-value = 0.9978
alternative hypothesis: variances are not identical

Warning messages:
1: In formals(fun) : argument is not a function
2: In formals(fun) : argument is not a function

HH documentation built on Nov. 28, 2020, 9:06 a.m.

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