Detecting dose–response using contrasts: asymptotic power and sample size determination for binomial data
Detecting dose–response using contrasts: asymptotic power and sample size determination for binomial data
复制标题
使用对比检测剂量反应：二项式数据的渐近功效和样本量确定
作者：
F. Bretz;L. Hothorn
最近，Stewart和Ruberg提出使用对比测试来检测剂量-反应关系。他们特别考虑了治愈率的双变量对比，并给出了几种定义适当系数集的可能性。本文从几个方面扩展了他们的工作。首先，导出了单次和多次对比检验的渐近幂表达式。其次，将众所周知的趋势检验重写为多重对比检验，从而缓解了选择适当对比系数的固有问题。第三，多元正态概率高效计算的最新成果克服了传统的基于模拟的数值计算方法。功率公式的修改允许计算给定类型I和II误差的样本量，自发速率和剂量响应形状。对小到中等样本量的功率研究的一些数值结果表明，标称功率是对实际功率的一个相当好的近似。一个临床试验的例子说明了结果的实际应用。版权所有©2002约翰威利父子有限公司
Recently, Stewart and Ruberg proposed the use of contrast tests for detecting dose–response relationships. They considered in particular bivariate contrasts for healing rates and gave several possibilities of defining adequate sets of coefficients. This paper extends their work in several directions. First, asymptotic power expressions for both single and multiple contrast tests are derived. Secondly, well known trend tests are rewritten as multiple contrast tests, thus alleviating the inherent problem of choosing adequate contrast coefficients. Thirdly, recent results on the efficient calculation of multivariate normal probabilities overcome the traditional simulation‐based methods for the numerical computations. Modifications of the power formulae allow the calculation of sample sizes for given type I and II errors, the spontaneous rate, and the dose–response shape. Some numerical results of a power study for small to moderate sample sizes show that the nominal power is a reasonably good approximation to the actual power. An example from a clinical trial illustrates the practical use of the results. Copyright © 2002 John Wiley & Sons, Ltd.