物质的生物活性(即毒性)可以通过实验来研究,其中处理是一系列单调增加(或减少)剂量的物质。此类研究的目的之一是确定最小有效剂量(有活性的最低剂量)。Williams(1971,1972)描述了这样的检验。Chow et al. (2008) 给出了执行功效分析和样本量的细节该测试的计算。
Test Procedure
Computing Power
Example
A pharmaceutical company needs to determine the minimum dose of a drug used to treat asthma. A 5-arm design including a placebo control and four active dose levels (0, 10mg, 20mg, 30mg, and 40 mg) of the test drug is planned. The response variable is percent change from baseline FEV1. Previous studies have found that σ = 25%. Determine the sample size required to detect a change of at least 10%, 15%, 20%, 30%, 40%, and 50% assuming 90% power and α = 0.05.
第一步:参数录入
第二步:结果输出
总样本量为580(或5组各116个)达到90%的功效,可检验零剂量平均值和治疗平均值之间的最小差异10,显着性水平(alpha)为0.05,标准偏差为25。
参考文献:
PASS说明书