Bioequivalence and Bioavailability Forum

Sample size [Study Assessment]

posted by d_labes – Berlin, Germany, 2012-10-11 15:10 (5001 d 00:57 ago) – Posting: # 9390
Views: 12,313

Dear Dr_Dan

❝ Upper acceptance limit = 125 %


❝   Lower acceptance limit = 80 %

❝       Expected ratio T/R = 95.00 %

❝             Target power = 80.00 %

❝         Intra-subject CV = 20.0 %
❝ 

❝   study     2x2x2        2x2x3       2x2x4 

❝   design  crossover   replicated   replicated 

❝  ------- ----------- ------------ ------------ 

❝     N        20          16           10
❝ 

❝          Estimated power = 83.46802 %

That looks like Bear if I'm right?
Bear has implemented only the power and sample size for the 2x2x2 crossover based on the non-central t-distribution approximation.
For the 3-period and 4-period replicate designs the rules n(2x2x3)=0.75*n(2x2x2) and n(2x2x4)=0.5*n(2x2x2) are used. But rules are rules only.

PowerTOST (exact via Owen's Q-function) gives you for your above settings:

Design   N    power

2x2x2   20  0.834680

2x2x3   14  0.817926

2x2x4   10  0.843312

Of course qualitatively and practically nearly the same.

—
Regards,

Detlew

Complete thread:

Failure of BE in fasting studies ABE1580 2012-10-09 15:42
- Failure of BE in fasting studies drgunasakaran1 2012-10-09 20:07
  - Failure of BE in fasting studies cakhatri 2012-10-10 07:34
    - Failure of BE in fasting studies Dr_Dan 2012-10-10 13:09
    - Different designs: why not? Helmut 2012-10-10 13:48
      - Different designs: why not? cakhatri 2012-10-12 10:42
    - Failure of BE in fasting studies drgunasakaran1 2012-10-10 19:14
      - Failure of BE in fasting studies ABE1580 2012-10-11 06:10
  - Failure of BE in fasting studies drsinghs 2012-10-11 09:28
    - Failure of BE in fasting studies Dr_Dan 2012-10-11 11:43
      - 1–β not necessarily = Δ Helmut 2012-10-11 13:05
      - Sample sized_labes 2012-10-11 13:10
        
        +partial replicate Helmut 2012-10-11 17:53

Sample size [Study As­sess­ment]

Complete thread:

Sample size [Study Assessment]