Bioequivalence and Bioavailability Forum • Precision of PowerTOST

Precision of PowerTOST [Power / Sample Size]

posted by Helmut – Vienna, Austria, 2017-12-09 18:00 (2625 d 16:42 ago) – Posting: # 18049
Views: 14,897

Hi mittyri,

❝ I tried to figure out the precision of PowerTOST estimations with the following code:

❝ scABELdata$power[j] <- power.scABEL(CV=0.8, n=54, theta0=0.95,

❝ design="2x3x3", nsims=10000,

❝ setseed=F)

❝ please correct if it is wrong.

I think so.
You got the right answer to a wrong question. For theta0=0.95 and targetpower=0.8 sample sizes are 57 for design="2x3x3" and 56 for design="2x2x3". Therefore, with 54 power will be <0.8 for both designs:

library(PowerTOST) power.scABEL(CV=0.8, theta0=0.95, n=57, design="2x3x3") # [1] 0.82231 power.scABEL(CV=0.8, theta0=0.95, n=54, design="2x3x3") # [1] 0.79917 power.scABEL(CV=0.8, theta0=0.95, n=56, design="2x2x3") # [1] 0.81545 power.scABEL(CV=0.8, theta0=0.95, n=54, design="2x2x3") # [1] 0.79883

❝ […] I would say that sample mean 80% in PowerTOST is a real unfortune :cool:

On the contrary; fortunately works as designed with the right sample sizes. :-D

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Helmut Schütz

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Complete thread:

Sample Size Estimation -Replicate design- BE limits cakhatri 2017-11-30 09:44 [Power / Sample Size]
- Reference-scaling: Don’t use FARTSSIE! Helmut 2017-11-30 10:58
  - Reference-scaling: Don’t use FARTSSIE? Astea 2017-11-30 22:50
    - Reference-scaling: Don’t use FARTSSIE! Helmut 2017-12-01 11:42
      - Reference-scaling: USE PowerTOST Astea 2017-12-01 14:16
        
        Reference-scaling: USE PowerTOST cakhatri 2017-12-04 06:00
        
        Reference-scaling: USE PowerTOST Helmut 2017-12-04 15:07
        
        Reference-scaling: USE PowerTOST cakhatri 2017-12-05 05:33
        
        Use PowerTOST d_labes 2017-12-06 09:52
        
        Use PowerTOST, not Endrényi L, Tóthfalusi L tables mittyri 2017-12-07 16:03
        
        Precision in Endrényi L, Tóthfalusi L tables d_labes 2017-12-07 18:21
        
        Precision of PowerTOST mittyri 2017-12-08 22:56
        
        Precision of PowerTOSTHelmut 2017-12-09 17:00
        
        Precision of PowerTOST mittyri 2017-12-09 21:05
        
        Precision of PowerTOST Astea 2017-12-10 00:10
        
        Precision of PowerTOST Helmut 2017-12-10 20:27
        
        Precision of PowerTOST Astea 2017-12-10 21:13
  - Reference-scaling: Don’t use FARTSSIE! pjs 2018-02-09 13:08
    - Reference-scaling: Don’t use FARTSSIE! Helmut 2018-02-09 20:15