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

Dear ElMaestro,

» »

» 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

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

One nitpicking: The

» »

*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

Regards,

Detlew

### Complete thread:

- Lower bound for power of two combined TOST? d_labes 2018-07-25 10:40
- Lower bound for power of two combined TOST? ElMaestro 2018-07-25 12:07
- Lower bound for power of two combined TOST?d_labes 2018-07-25 14:46
- Appendix D mittyri 2018-07-26 00:07
- Appendix D d_labes 2018-07-26 13:41

- Appendix D mittyri 2018-07-26 00:07

- Lower bound for power of two combined TOST?d_labes 2018-07-25 14:46
- Use of lower bound for power of two combined TOST d_labes 2018-07-26 14:29
- Use of lower bound for power of two combined TOST Ben 2018-08-06 18:11
- Use of lower bound for power of two combined TOST d_labes 2018-08-07 11:50

- Use of lower bound for power of two combined TOST Ben 2018-08-06 18:11

- Lower bound for power of two combined TOST? ElMaestro 2018-07-25 12:07