Bioequivalence and Bioavailability Forum

Precision of PowerTOST [Power / Sample Size]

posted by mittyri – Russia, 2017-12-08 23:56 (2323 d 03:10 ago) – Posting: # 18048
Views: 13,879

Dear Detlew,

thank you for clarification
I tried to figure out the precision of PowerTOST estimations with the following code:
library("ggplot2")
library("PowerTOST")
reps <- 1E6
scABELdata <- data.frame(rep = 1:reps)
for(i in 1:reps){
  set.seed(i)
  scABELdata$power[i] <- power.scABEL(CV=0.8, n=54, theta0=0.95, design="2x3x3", nsims=10000, setseed=F)
}

ggplot(scABELdata, aes(power))+
  geom_density(fill = 2, alpha = 0.3)+
  theme_bw() +
  ggtitle(sprintf("%d reps: Mean is %.4f, SD is %.4f; %.2f %% obs are less than 0.8", reps, mean(scABELdata$power), sd(scABELdata$power), sum(scABELdata$power<0.8)/length(scABELdata$power)*100))

please correct if it is wrong.
The resulted plot:


BAsed on the mean and se calculated from sd and n=20 I would say that sample mean 80% in PowerTOST is a real unfortune

❝ BTW: Both Laszlos recommend to use PowerTOST if they were asked .

Fully agree and thanks again for this wonderful package.

Complete thread:

• Sample Size Estimation -Replicate design- BE limits cakhatri 2017-11-30 09:44 
  • 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 PowerTOSTmittyri 2017-12-08 22:56
                  • Precision of PowerTOST Helmut 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