welch_anova_test {rstatix}

Welch One-Way ANOVA Test

Description

Tests for equal means in a one-way design (not assuming equal variance). A wrapper around the base function oneway.test(). This is is an alternative to the standard one-way ANOVA in the situation where the homogeneity of variance assumption is violated.

Usage

welch_anova_test(data, formula)

Arguments

data

a data frame containing the variables in the formula.

formula

a formula specifying the ANOVA model similar to aov. Can be of the form y ~ group where y is a numeric variable giving the data values and group is a factor with one or multiple levels giving the corresponding groups. For example, formula = TP53 ~ cancer_group.

Value

return a data frame with the following columns:

• .y.: the y variable used in the test.

• n: sample count.

• statistic: the value of the test statistic.

• p: p-value.

• method: the statistical test used to compare groups.

Examples

# Load data
#:::::::::::::::::::::::::::::::::::::::
data("ToothGrowth")
df <- ToothGrowth
df$dose <- as.factor(df$dose)

# Welch one-way ANOVA test (not assuming equal variance)
#:::::::::::::::::::::::::::::::::::::::::
df %>% welch_anova_test(len ~ dose)

# Grouped data
#:::::::::::::::::::::::::::::::::::::::::
df %>%
  group_by(supp) %>%
  welch_anova_test(len ~ dose)