This paper considers the problem of critical value calculations for multiple comparisons of three normal means based on Lee et al.’s [12] one-sided multiple comparison test (OMCT) procedure. Lee et al. [12] provided critical values for the balanced cases only. The OMCT procedure is a generalization of Hayter’s [5] one-sided studentized range test (OSRT) procedure. The computation of critical values for the OMCT procedure is more complicated than that in Hayter et al.  [7] for the OSRT procedure. R programs that use one-dimensional numerical integration have been developed which will allow experimenters to easily obtain the required critical values and p-values.

critical values, multiple comparisons, one-sided studentized range test, polar coordinates, unbalanced one-way ANOVA.