An unbiased test for the bioequivalence problem

Abstract
It is shown that the standard two one-sided tests procedure for bioequivalence is a biased test. Better tests exist. In this paper, an unbiased $\alpha$-level test and other tests which are uniformly more powerful than the two one-sided tests procedure are constructed. Its power can be noticeably larger than that of the $\alpha$-level two one-sided tests procedure.