ON THE USE OF A PILOT SAMPLE FOR SAMPLE-SIZE DETERMINATION
ON THE USE OF A PILOT SAMPLE FOR SAMPLE-SIZE DETERMINATION
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DOI：
10.1002/sim.4780141709
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发表时间：
1995-09-15
影响因子：
2
通讯作者：
BROWNE, RH
中科院分区：
文献类型：
--
作者：
BROWNE, RH
为了计算达到t检验的计划功效所需的样本量，需要估计总体标准差σ。如果使用来自小型试点研究的样本标准差作为sigma的估计值，则计划研究的实际功效很可能小于计划功效。Monte Carlo模拟表明，使用100（1 -伽马）%的sigma单侧置信上限将提供足以在至少100（1 -伽马）%的此类试验中实现计划功效的样本量。
To compute the sample size needed to achieve the planned power for a t-test, one needs an estimate of the population standard deviation sigma. If one uses the sample standard deviation from a small pilot study as an estimate of sigma, it is quite likely that the actual power for the planned study will be less than the planned power. Monte Carlo simulations indicate that using a 100(1 - gamma) per cent upper one-sided confidence limit on sigma will provide a sample size sufficient to achieve the planned power in at least 100(1 - gamma) per cent of such trials.