Bioequivalence and Bioavailability Forum • Sample Size II

Sample Size II [Power / Sample Size]

posted by BE-proff – 2016-12-28 09:14 (3115 d 23:46 ago) – Posting: # 16892
Views: 10,798

Hi All,

Let's say I want to calculate sample size based on results of a previous study.

I have the following data:
n=20
CV=0.18 (for Cmax and AUC) ;-)

GMR1 = 0.97
GMR2=1.19

If to calculate size based on GMR1 I think it's better to use a script:

sampleN.TOST(CV=0.18, theta0=0.95)



+++++++++++ Equivalence test - TOST +++++++++++

            Sample size estimation

-----------------------------------------------

Study design:  2x2 crossover 

log-transformed data (multiplicative model)



alpha = 0.05, target power = 0.8

BE margins = 0.8 ... 1.25 

True ratio = 0.95,  CV = 0.18



Sample size (total)

 n     power

16   0.820357

if to use GMR = 1.19 we see something terrible:

sampleN.TOST(CV=0.18, theta0=1.19)



+++++++++++ Equivalence test - TOST +++++++++++

            Sample size estimation

-----------------------------------------------

Study design:  2x2 crossover 

log-transformed data (multiplicative model)



alpha = 0.05, target power = 0.8

BE margins = 0.8 ... 1.25 

True ratio = 1.19,  CV = 0.18



Sample size (total)

 n     power

166   0.803570

- too many people... :no:

What to do in such situations? :confused:

Complete thread:

Sample Size IIBE-proff 2016-12-28 08:14 [Power / Sample Size]
- Please see the answer to your previous post mittyri 2016-12-28 09:17
  - Please see the answer to your previous post BE-proff 2016-12-28 10:35
    - Another Master's answer mittyri 2016-12-28 11:38
- Sample Size II ElMaestro 2016-12-28 10:52
- Expected power answer d_labes 2016-12-28 13:42
- Sample Size and regulators DavidManteigas 2016-12-28 18:11
  - Sample Size and sponsors d_labes 2016-12-28 19:24
    - Sample Size and spongulators ElMaestro 2016-12-28 22:22
  - Sample Size and regulators mittyri 2016-12-29 11:44
  - Sample Size and regulators Helmut 2016-12-29 12:39