Published online by Cambridge University Press: 01 January 2025
Moses has proposed a nonparametric test of the null hypothesis that two samples, say a treatment and a control group, have been drawn from the same population; his test is designed to be sensitive to the alternative hypothesis that the treatment group is extreme in either or both directions as compared with the controls. This paper presents a test of similar character, except that rather than being based on a range of the control group ranks, it depends upon the variance of those ranks. This has the advantage of making ties less troublesome. Tables of significance values are presented for some small sample sizes. A normal approximation is developed and seen to be useful.
This research was partially sponsored by a Public Health Biostatistics Training Grant at Stanford University.
I wish to thank Professor Lincoln E. Moses of Stanford University for suggesting the problem, and for his invaluable assistance in the preparation of this paper.