Rank-based method for controlling experiment-wise error. Assume normality of the distribution for the variable of interest.
tukey.kruskal.test(resp, grp, alpha = 0.05)
A logical vector for every combinaison of two groups. TRUE
if the distribution in one group is significantly different from the distribution in the other group.
vector containing the values for the variable of interest.
vector specifying in which group is each observation.
level of the test.
The original Tuckey HSD procedure is supposed to be applied for equal sample sizes. However, the tukey.kruskal.test
function performs the Tukey-Kramer procedure that works for unequal sample sizes.
J.J. Higgins, (2004), Introduction to Modern Nonparametric Statistics, Brooks/Cole, Cengage Learning.