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Sample size determination for proving equivalence based on the ratio of two means for normally distributed data
Author(s) -
Hauschke Dieter,
Kieser Meinhard,
Diletti Edgar,
Burke Martin
Publication year - 1999
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/(sici)1097-0258(19990115)18:1<93::aid-sim992>3.0.co;2-8
Subject(s) - equivalence (formal languages) , sample size determination , statistics , confidence interval , intersection (aeronautics) , mathematics , sample (material) , population , computer science , discrete mathematics , demography , chemistry , chromatography , engineering , aerospace engineering , sociology
Equivalence trials aim to demonstrate that two treatments do not differ by more than a prespecified clinically irrelevant amount. We consider the problem when equivalence is defined in terms of the ratio of population means and the original (untransformed) data are normally distributed. Application of the intersection‐union principle to the test proposed by Sasabuchi results in a two one‐sided tests procedure of size α . We give the associated 100 (1−2 α ) per cent confidence interval and derive the exact methods for calculation of power and sample sizes for the parallel group design and the two‐period cross‐over. We present tables and figures of required sample sizes and achieved power. Copyright © 1999 John Wiley & Sons, Ltd.