welch.test: Welch's Heteroscedastic F Test and Welch's Heteroscedastic F...

In onewaytests: One-Way Tests in Independent Groups Designs

Welch's Heteroscedastic F Test and Welch's Heteroscedastic F Test with Trimmed Means and Winsorized Variances

Description

welch.test performs Welch's heteroscedastic F test and Welch's heteroscedastic F test with trimmed means and Winsorized variances.

Usage

welch.test(formula, data, rate = 0, 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.
rate	the rate of observations trimmed and winsorized from each tail of the distribution. If rate = 0, it performs Welch's heteroscedastic F test. Otherwise, Welch's heteroscedastic F test with trimmed means and Winsorized variances is performed. Default is set to rate = 0.
alpha	the level of significance to assess the statistical difference. 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 with class "owt" containing the following components:

statistic	the value of the test statistic with a name describing it.
parameter	the parameter(s) of the approximate F distribution of the test statistic.
p.value	the p-value of the test.
alpha	the level of significance to assess the statistical difference.
method	the character string "Welch's Heteroscedastic F Test" or "Welch's Heteroscedastic F Test with Trimmed Means and Winsorized Variances" depending on the choice.
rate	the rate of observations trimmed and winsorized from each tail of the distribution.
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)

Osman Dag

References

Dag, O., Dolgun, A., Konar, N.M. (2018). onewaytests: An R Package for One-Way Tests in Independent Groups Designs. The R Journal, 10:1, 175-199.

Welch, B. L.(1951). On the Comparison of Several Mean Values: An Alternative Approach. Biometrika, 38, 330-336.

Examples

library(onewaytests)

welch.test(Sepal.Length ~ Species, data = iris)
welch.test(Sepal.Length ~ Species, data = iris, rate = 0.1)

out <- welch.test(Sepal.Length ~ Species, data = iris)
paircomp(out)

onewaytests documentation built on Oct. 2, 2023, 1:09 a.m.