Zhao Yan D, Rahardja Dewi, Qu Yongming
Eli Lilly and Company, Indianapolis, IN 46285, USA.
Stat Med. 2008 Feb 10;27(3):462-8. doi: 10.1002/sim.2912.
In this paper we study sample size calculation methods for the asymptotic Wilcoxon-Mann-Whitney test for data with or without ties. The existing methods are applicable either to data with ties or to data without ties but not to both cases. While the existing methods developed for data without ties perform well, the methods developed for data with ties have limitations in that they are either applicable to proportional odds alternatives or have computational difficulties. We propose a new method which has a closed-form formula and therefore is very easy to calculate. In addition, the new method can be applied to both data with or without ties. Simulations have demonstrated that the new sample size formula performs very well as the corresponding actual powers are close to the nominal powers.
在本文中，我们研究了用于有结或无结数据的渐近Wilcoxon-Mann-Whitney检验的样本量计算方法。现有方法要么适用于有结数据，要么适用于无结数据，但不适用于这两种情况。虽然为无结数据开发的现有方法表现良好，但为有结数据开发的方法存在局限性，即它们要么适用于比例优势备择假设，要么存在计算困难。我们提出了一种新方法，该方法具有封闭形式的公式，因此非常易于计算。此外，新方法可应用于有结或无结数据。模拟表明，新的样本量公式表现良好，因为相应的实际功效接近名义功效。
