Bioequivalence and Bioavailability Forum

Dear Martin, dear Helmut!

Strange!? Writing down the sentence "the calculated sample mean should not differ more than 1.3 standard deviations (SDs) to the known value" as formula, with µ₀ the known value

-1.3*SD < µ - µ0 < 1.3*SD
rearranged
-1.3 < (µ - µ0)/SD < 1.3

it strongly reminds me of a thing that is called "scaled ABE" in the context of BE studies, but here as a one group test. Isn't it?

But in the simple application of the above equation, as the sentence suggests, the method is not described properly I think. There is evidence that one should use 95% confidence intervals for the criterion (µ - µ₀)/SD or a linearized version of it.

Additionally: Where the constant 1.3 comes from remains questionable.
Wellek^[1] proposes 0.36 (strict) or 0.74 (liberal) in the context of a two group test.

BTW: (µ - µ₀)/sd is the effect size in the sense of Cohen.

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^[1] S. Wellek
"Testing Statistical Hypotheses of Equivalence"
Chapman & Hall / CRC
Boca Raton 2000