Bioequivalence and Bioavailability Forum • The Power at limits

The Power at limits [🇷 for BE/BA]

posted by d_labes – Berlin, Germany, 2009-10-07 13:32 (6089 d 02:41 ago) – Posting: # 4312
Views: 45,783

Dear All!

Back from the date with the Blonde downstairs an having some spare time ;-)

,

Seems ElMaestro's question is able to put the power to the limits.
Here results of power.equivalence.md around N=6:

R code:

library(MBESS)



alpha    <- 0.05

logscale <- TRUE

ltheta1  <- 0.8

ltheta2  <- 1/ltheta1

ldiff    <- 0.95

CV       <- 0.65                # added [HS]

sigma    <- sqrt(log(1+(CV)^2)) # added [HS]

n        <- c(4,6,8,10,12,14,16)

df       <- n-2

pow      <- mapply(power.equivalence.md,n=n,nu=df, MoreArgs =list(alpha, logscale, ltheta1, ltheta2, ldiff, sigma))

res      <- data.frame(n=n, power=pow)

res

Result:


   n        power

1  4 0.0045417784

2  6 0.0016203829

3  8 0.0009763342

4 10 0.0007993335

5 12 0.0007966979

6 14 0.0009067329

7 16 0.0011306148

I would expect power is increasing with increasing n.
Or miss I here something?

BTW: My SAS code shows the same effect.
All this is hairsplitting of course.

Edit: Added two lines above to allow copy-pasting of code to R-console. BTW, change the sample size vector to n<-c(4,6,8,10,12,14,16,38,40,152,154,344,346) and watch (the gamma-function needs the faculty, which runs out of steam - at least on 32-bit operating systems). [Helmut]

—
Regards,

Detlew

Complete thread:

non-central t, power, R: ElMaestro 2009-10-03 19:05
- non-central t, power, R: Helmut 2009-10-03 21:45
  - non-central t, power, R: ElMaestro 2009-10-04 21:51
    - non-central t, power, R: Helmut 2009-10-04 23:58
- non-central t is not the question d_labes 2009-10-05 12:58
  - SAS -> R -> SAS Helmut 2009-10-05 14:53
    - Lost in translation d_labes 2009-10-06 14:31
      - Lost in translation Helmut 2009-10-06 14:42
        
        Macacus cynocephalus d_labes 2009-10-06 15:14
        
        Lost in translation Helmut 2009-10-06 21:46
  - non-central t is not the question ElMaestro 2009-10-05 17:32
    - Power of TOST in R d_labes 2009-10-06 16:45
      - Power of TOST (R package MBESS) Helmut 2009-10-07 02:18
        
        Power of TOST (R package MBESS) d_labes 2009-10-07 08:46
        
        Power of TOST (R package MBESS) Helmut 2009-10-07 12:38
      - The Power at limitsd_labes 2009-10-07 11:32
        
        Power at limits 2 d_labes 2009-10-07 15:15
        
        package MBESS Helmut 2009-10-07 22:36
        
        Package MBESS and Power curiosity d_labes 2009-10-15 14:57
        
        Package MBESS and Power curiosity ElMaestro 2009-10-17 12:26
        
        Apfelstrudel and EFG 2.01 Helmut 2009-10-17 13:44
        EFG and another power curiosity d_labes 2009-10-20 11:35
        
        EFG and another power curiosity ElMaestro 2009-11-23 19:03
        
        EFG and another power curiosity Helmut 2009-11-23 19:17
- non-central t, power, R: yjlee168 2009-10-07 00:08
  - PASS Helmut 2009-10-07 01:16
    - PASS yjlee168 2009-10-12 23:17
- R code for power ElMaestro 2009-10-09 11:32
  - Belgian beer ? Ohlbe 2009-10-09 11:50
  - Another one - R code for power of TROST d_labes 2009-10-09 13:50