ansari.test {vartest}

Ansari Bradley Test

Description

ansari.test performs Ansari Bradley variance homogeneity test.

Usage

ansari.test(formula, data, alpha = 0.05, na.rm = TRUE, verbose = TRUE)

Arguments

formula

a formula of the form lhs ~ rhs where lhs gives the sample values and rhs the corresponding groups.

data

a tibble or data frame containing the variables in formula.

alpha

the level of significance to assess variance homogeneity. Default is set to alpha = 0.05.

na.rm

a logical value indicating whether NA values should be stripped before the computation proceeds.

verbose

a logical for printing output to R console.

Value

A list containing the following components:

statistic

the corresponding test statistic.

parameter

the parameter(s) of the approximate chi squared distribution of the test statistic.

p.value

the p-value of the test.

method

the character string "Ansari Bradley Test".

data

a data frame containing the variables in which NA values (if exist) are removed.

formula

a formula of the form lhs ~ rhs where lhs gives the sample values and rhs the corresponding groups.

Author(s)

Gozde Cosar and Osman Dag

References

Conover, W.J., Johnson, M.E., Johnson, M.M. (1981). A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data. Technometrics, 23:4, 351-361.

See Also

ansari_test

Examples

library(vartest)

ansari.test(Sepal.Length ~ Species, data = iris)