Nam J
Mathematical Statistics and Applied Mathematics Section, National Cancer Institute, Bethesda, Maryland 20892.
Biometrics. 1992 Jun;48(2):389-95.
Woolson, Bean, and Rojas (1986, Biometrics 42, 927-932) present a simple approximation of sample size for Cochran's (1954, Biometrics 10, 417-451) test for detecting association between exposure and disease. It is useful in the design of case-control studies. We derive a sample size formula for Cochran's statistic with continuity correction which guarantees that the actual Type I error rate of the test does not exceed the nominal level. The corrected sample size is necessarily larger than the uncorrected one given by Woolson et al. and the relative difference between the two sample sizes is considerable. Allocation of equal number of cases and controls within each stratum is asymptotically optimal when the costs per case and control are the same. When any effect of stratification is absent, Cochran's stratified test, although valid, is less efficient than the unstratified one except for the important case of a balanced design.
伍尔森、比恩和罗哈斯（1986年，《生物统计学》42卷，927 - 932页）提出了一种用于科克伦（1954年，《生物统计学》10卷，417 - 451页）检验的样本量简单近似值，该检验用于检测暴露与疾病之间的关联。它在病例对照研究的设计中很有用。我们推导出了带有连续性校正的科克伦统计量的样本量公式，该公式保证了检验的实际第一类错误率不超过名义水平。校正后的样本量必然大于伍尔森等人给出的未校正样本量，并且两个样本量之间的相对差异相当大。当每个病例和对照的成本相同时，在每个分层内分配相等数量的病例和对照在渐近意义上是最优的。当不存在分层的任何影响时，科克伦分层检验虽然有效，但除了平衡设计这种重要情况外，比未分层检验的效率更低。
