med1way: Heteroscedastic one-way ANOVA for medians.
Description
This function computes a one-way ANOVA for the medians. Homoscedasticity assumption not required. There shouldn't be too many ties.
Usage
med1way(formula, data, iter = 1000, ...)
Value
Returns an object of class med1way containing:
test
F-value of the test statistic
crit.val
critical value
p.value
p-value
call
function call
Arguments
formula
an object of class formula.
data
an optional data frame for the input data.
iter
number of iterations to determine critical value.
...
currently ignored.
Details
Evaluating the test statistic using the df proposed in the literature can result in the actual level being less than the nominal level, (i.e., around 0.02-0.025 when testing at the 0.05 level and the sample size is small). A better strategy is to simulate the critical
value and computing the p-value accordingly, as implemented in this function.
References
Wilcox, R. (2012). Introduction to Robust Estimation and Hypothesis Testing (3rd ed.). Elsevier.