Internal pilot studies I:: Type I error rate of the naive t-test
Internal pilot studies I:: Type I error rate of the naive t-test
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DOI：
10.1002/(sici)1097-0258(19991230)18:24
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发表时间：
1999-12-30
影响因子：
2
通讯作者：
Proschan, M
中科院分区：
文献类型：
--
作者：
Wittes, J;Schabenberger, O;Proschan, M
当使用揭盲中期数据重新计算样本量时，在研究结束时使用常规t检验可能导致I类错误率升高。本文描述了一种数值求积研究，以计算真实的拒绝概率，作为重新计算时间、可检测治疗效果的大小以及猜测与真实方差之比的函数。我们考虑了“限制”设计，即那些要求最终样本量至少与最初计算的大小一样大的设计，以及“无限制”设计，我们的研究结果表明，在第一类错误率的偏差往往是可以忽略不计的，特别是在限制性设计，一些参数集，然而，诱导非平凡的偏差在非限制性设计，版权（C）1999年约翰威利父子公司，有限公司。
When sample size is recalculated using unblinded interim data, use of the usual t-test at the end of a study may lead to an elevated type I error rate. This paper describes a numerical quadrature investigation to calculate the true probability of rejection as a function of the time of the recalculation, the magnitude of the detectable treatment effect, and the ratio of the guessed to the true variance, We consider both 'restricted' designs, those that require final sample size at least as large as the originally calculated size, and 'unrestricted' designs, those that permit smaller final sample sizes than originally calculated, Our results indicate that the bias in the type I error rate is often negligible, especially in restricted designs, Some sets of parameters, however, induce non-trivial bias in the unrestricted design, Copyright (C) 1999 John Wiley & Sons, Ltd.