DunnTest: Dunn's Test for Multiple Comparisons (Non-Parametric)
Description
Performs Dunn's test for pairwise comparisons following a Kruskal-Wallis test.
Suitable for non-parametric data (ordinal or non-normal), using rank sums.
Includes Holm correction by default for multiple comparisons.
An object of class "dunn" and "comparaciones", including:
Resultados: Data frame with group comparisons, z-values, raw and adjusted p-values, and significance.
Promedios: Mean ranks of each group.
Orden_Medias: Group names ordered from highest to lowest rank.
Metodo: "Dunn (no paramétrico)".
Arguments
formula
A formula of the form y ~ group.
data
A data frame containing the variables.
alpha
Significance level (default is 0.05).
method.p
Method for p-value adjustment (default is "holm").
Details
Advantages:
- Simple and widely used non-parametric alternative to Tukey's test.
- Handles unequal sample sizes.
- Compatible with various p-value corrections (e.g., Holm, Bonferroni).
Disadvantages:
- Less powerful than DSCF or Conover when sample sizes vary widely.
- Requires ranking all data and can be conservative depending on adjustment.
References
Dunn, O. J. (1964). Multiple comparisons using rank sums. *Technometrics*, 6(3), 241–252. tools:::Rd_expr_doi("10.1080/00401706.1964.10490181")