T2Test {Analitica} | R Documentation |
Tamhane's T2 Post Hoc Test
Description
Performs the Tamhane T2 test for pairwise comparisons after an ANOVA model, assuming unequal variances and/or unequal sample sizes. This test is appropriate when the assumption of homogeneity of variances is violated, such as when Levene's test or Bartlett's test is significant.
Usage
T2Test(modelo, alpha = 0.05)
Arguments
modelo |
An object of class |
alpha |
Significance level (default is 0.05). |
Details
The test uses a modified t-test with Welch-Satterthwaite degrees of freedom and a conservative approach to control for multiple comparisons.
Advantages: - Controls Type I error under heteroscedasticity. - No assumption of equal sample sizes.
Disadvantages: - Conservative; may reduce power. - Not as powerful as Games-Howell in some contexts.
Value
An object of class "tamhanet2"
and "comparaciones"
, containing:
-
Resultados
: A data frame with pairwise comparisons, mean differences, t-values, degrees of freedom, p-values, and significance codes. -
Promedios
: A named numeric vector of group means. -
Orden_Medias
: A character vector with group names ordered from highest to lowest mean. -
Metodo
: A character string indicating the method used ("Tamhane T2").
References
Tamhane, A. C. (1977). "Multiple comparisons in model I one-way ANOVA with unequal variances." Communications in Statistics - Theory and Methods, 6(1), 15–32. <https://doi.org/10.1080/03610927708827524>
Examples
data(d_e, package = "Analitica")
mod <- aov(Sueldo_actual ~ as.factor(labor), data = d_e)
resultado <- T2Test(mod)
summary(resultado)
plot(resultado)