摘要
目的：本文提出一种广义非中心法以适应终检．它由经典非中心法衍变而来，用于多样本生存率检验所需样本量的测定．方法：其第１步继承经典方法。按已有的非中心卡方分布表和经典ｒ×２卡方统计量非中心参数表达式得出所需同源有效样本量；第２步由同源有效样本量在Ｗｅｉｂｕｌｌ生存分布下的参数表达式按预定终检率反推出所需样本量，并以逐个迭代实现样本量的分配．结果：与已有的校正终检样本量测定方法相比，该方法的特点是，与多样本生存率检验相匹配；摆脱了指数分布的假设；在无终检时还原为经典方法；其观测功效和预定功效精确吻合．结论：该方法可用于多样本癌症临床研究方案的设计．附有工作实例描述设计过程．
Objective: A generalized non-central procedure is proposed for covering censorship. It is derived from its classical counterpart and appllied in determining the sample size required in the poly-sample survival rate test. Methods: The first step inherites the classical procedure for determining the required homogenetic effective sample size based on existing tables of the non- central chi square distribution and expression for the non-centrality parameter of the classical r × 2 chi square statistic. The second step yields the required sample size at a given censoring rate, which is operated inversely from the parametric expression of the homogenetic effective sample size under Weibull survival distributions. The sample allocations are realized by the item-by-item iteration. Results: By contrast with the existing procedures for sample size determination adjusted censoring, the procedure has such characteristics as that it is matched with the poly-sample survival rate test, that it is free from the assumption of exponential distributions, that it reduces to its classical counterpart when there is no censoring, and that the observed power of the test coincides with the prescribed power. Conclusion: The procedure can be applied to planning poly-sample clinical cancer studies. A worked example illustrates the planning process.
出处
《应用概率统计》
CSCD
北大核心
1999年第4期337-344,共8页
Chinese Journal of Applied Probability and Statistics
