rcompanion (version 2.4.30)

pairwiseMedianMatrix: Pairwise Mood's median tests with matrix output

Description

Conducts pairwise Mood's median tests across groups.

Usage

pairwiseMedianMatrix(
  formula = NULL,
  data = NULL,
  x = NULL,
  g = NULL,
  digits = 4,
  method = "fdr",
  ...
)

Value

A list consisting of: a matrix of p-values; the p-value adjustment method; a matrix of adjusted p-values.

Arguments

formula

A formula indicating the measurement variable and the grouping variable. e.g. y ~ group.

data

The data frame to use.

x

The response variable as a vector.

g

The grouping variable as a vector.

digits

The number of significant digits to round output.

method

The p-value adjustment method to use for multiple tests. See stats::p.adjust.

...

Additional arguments passed to coin::median_test.

Author

Salvatore Mangiafico,

Details

The input should include either formula and data; or x, and g.

Mood's median test compares medians among two or more groups. See http://rcompanion.org/handbook/F_09.html for futher discussion of this test.

The pairwiseMedianMatrix function can be used as a post-hoc method following an omnibus Mood's median test. It passes the data for pairwise groups to coin::median_test.

The matrix output can be converted to a compact letter display, as in the example.

References

http://rcompanion.org/handbook/F_09.html

See Also

pairwiseMedianTest

Examples

data(PoohPiglet)
PoohPiglet$Speaker = factor(PoohPiglet$Speaker,
                          levels = c("Pooh", "Tigger", "Piglet"))
PT = pairwiseMedianMatrix(Likert ~ Speaker,
                          data   = PoohPiglet,
                          exact  = NULL,
                          method = "fdr")$Adjusted
PT                           
library(multcompView)
multcompLetters(PT,
                compare="<",
                threshold=0.05,
                Letters=letters)