Two at a Time [Power / Sample Size]

posted by Helmut Homepage – Vienna, Austria, 2022-09-22 11:30 (78 d 14:03 ago) – Posting: # 23313
Views: 678

Hi XH7081,

❝ First of all thank you for the wonderful PowerTOST package!


Welcome. THX to Detlew Labes and Benjamin Lang. Both did much more than myself.

❝ If I want to design an injection site study to compare the relative bioavailability at 3 different injection site, say T1, T2 vs R, in either crossover design or parallel design, is it correct to use the R code below:


In principle yes but as already mentioned by Divyen, theta0 = 1 should not be used.

❝ I also saw some posts suggest doing "two at a time" test, which will use the 2x2 design as follows (which gave essentially the same sample size as the 3x6x3 design above since I need to round up to 6X, so 40 becomes 42). Is this thought process correct?


See this article and click on Show hide/details

❝ Parallel design (3 arms, assuming true theta=1, pooled CV=0.4). R results indicate I need 132 total subjects (44 subjects per arm), not considering drop out etc. Is it correct, or the 132 is for 2 arms (66 per arm) and I actually need 198 total subjects?


Yes.

Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz
[image]

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

UA Flag
Activity
 Admin contact
22,436 posts in 4,696 threads, 1,599 registered users;
30 visitors (0 registered, 30 guests [including 15 identified bots]).
Forum time: 00:34 CET (Europe/Vienna)

Meta-analysis – A technique for adding apples and pears
together to produce turkeys.    Stephen Senn

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