A Generalized Wilcoxon Test for Comparing Arbitrarily Singly-censored Samples.

where F1, F2 are cumulative distributions (discrete or continuous) of the observations and Tis their upper limit. The test is shown to be asymptotically normal and consistent against one-sided alternatives F1(t) < F2(t) (t ~ T) and against two-sided alternatives where either F1(t) < F2(t) or F1(t) > F2(t) (t ~ T). The asymptotic efficiency of the test relative to the efficient parametric test when the distributions are exponential is at least 0·75 and increases ";th degree of censoring. When H0 is true, the test is not seriously affected by real differences in the percentage censored in the two groups. Some comparisons are made for five cases of varying degrees of censoring and tying between probabilities from the exact test and those from the proposed test and these suggest the test is appropriate under certain conditions when the sample size is five in each group. A worked example is presented and some discussion is given to further problems.