Lower bound for power of two combined TOST? [Power / Sample Size]

posted by d_labes  – Berlin, Germany, 2018-07-25 14:46 (749 d 07:42 ago) – Posting: # 19100
Views: 3,333

Dear ElMaestro,

» »

Power >= PAUC + PCmax - (2 - 1)

where PAUC is the estimate of power for AUC and PCmax is the estimate of power for Cmax.

» Surely that's either wrong or an approximation that has some validity within a set of strict conditions. I have not read that work or reference 918, but it looks outright wrong.

Here we are two.
You may read under the link

https://books.google.de/books?id=e3byCOxj8FoC&pg=PA45

some more sparse details. Unfortunately the Appendix D with a proof of that formula is not available in Gooooogle books.

» With that equation power could become negative, go figure.

One nitpicking: The lower bound of power could become negative if both powers are <0.5, values no one would use in estimating sample sizes. If such a bound is reasonable is of course highly questionable.

Regards,

Detlew

Complete thread:

Activity
 Admin contact
21,008 posts in 4,379 threads, 1,460 registered users;
online 16 (1 registered, 15 guests [including 12 identified bots]).
Forum time: Wednesday 22:28 CEST (Europe/Vienna)

Statistics is the art of never having to say you’re wrong.
Variance is what any two statisticians are at.    C.J. Bradfield

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5