## Critical values for the robust rank-order test

### Nick Feltovich

The nonparametric Wilcoxon-Mann-Whitney test is
commonly used by practitioners for detecting differences in location (mean,
median) between two samples. Earlier work (e.g., Zimmerman (1987), Feltovich
(2003)) has shown that this test has a number of disadvantages, most of which
are ameliorated by the robust rank-order test (Fligner and
Pollicello (1981)). Use of the robust rank-order
test has been limited, partly because exact critical values have heretofore
been available for only a small number of sample-size values, and not for all
of the commonly-used levels of significance. This note expands what is known
about the distribution of the robust rank-order test statistic; critical values
are given for more sample sizes and for more levels of significance.

Feltovich, Nick (2005), "Critical values for the robust rank-order test," *Communications
in Statistics - Simulation and Computation* 34 (3), pp. 525-547.
DOI: 10.1081/SAC-200068395.