Estimating the sample size for a t-test using an internal pilot.
Estimating the sample size for a t-test using an internal pilot.
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DOI：
10.1002/(sici)1097-0258(19990715)18:13
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发表时间：
1999-07
影响因子：
2
通讯作者：
J. Denne;C. Jennison
中科院分区：
文献类型：
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作者：
J. Denne;C. Jennison
如果 t 检验的样本量是根据方差的先前估计来计算的，则感兴趣的治疗差异的检验功效对于方差的错误指定并不稳健。我们提出基于 Stein 两阶段测试的两种治疗比较的 t 检验，其中涉及使用内部试点来估计方差，从而估计所需的最终样本量。我们评估了我们的程序的性能，并表明它比针对同一问题的现有方法更能控制 I 类和 II 类错误率。我们还提出了选择内部试点规模的规则，并表明这在程序效率方面是合理的。
If the sample size for a t-test is calculated on the basis of a prior estimate of the variance then the power of the test at the treatment difference of interest is not robust to misspecification of the variance. We propose a t-test for a two-treatment comparison based on Stein's two-stage test which involves the use of an internal pilot to estimate variance and thus the final sample size required. We evaluate our procedure's performance and show that it controls the type I and II error rates more closely than existing methods for the same problem. We also propose a rule for choosing the size of the internal pilot, and show that this is reasonable in terms of the efficiency of the procedure.