Bioequivalence and Bioavailability Forum • Sims

Sims [🇷 for BE/BA]

posted by Helmut – Vienna, Austria, 2010-04-27 03:36 (5532 d 14:29 ago) – Posting: # 5242
Views: 62,170

Dear D. Labes,

you have already outed yourself as a passionate wheel-reinventer, but why don't you simply go with the Welch-test (orwhatsover for unequal variances)? Since our Capt'n luuuvs simulations, I recycled some of his code to play width:

sims   <- 10000

MeanT  <- 95

MeanR  <- 100

CVT    <- 0.25

CVR    <- 0.40

nCons  <- 0

nAnti  <- 0

nT     <- 12

nR     <- 10

for (iter in 1:sims)

  {

    lnPKT  <- rnorm(n=nT,mean=MeanT,sd=CVT*MeanT) 

    lnPKR  <- rnorm(n=nR,mean=MeanR,sd=CVR*MeanR) 

    WelchRes <- t.test(lnPKT,lnPKR,conf.level=0.9)

    TtestRes <- t.test(lnPKT,lnPKR,var.equal=TRUE,conf.level=0.9)

    WidthW <- abs(WelchRes$conf.int[1]-WelchRes$conf.int[2])

    WidthT <- abs(TtestRes$conf.int[1]-TtestRes$conf.int[2])

    if (WidthT<WidthW){

      nAnti <- nAnti+1

      }else{

      nCons <- nCons+1

    }

  }

result  <- paste(paste("t-test compared to Welch-test\n"),

          paste("Conservative = ", 100*nCons/sims, "%\n"),

          paste("Liberal = ", 100*nAnti/sims, "%\n"))

cat(result)

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

Parallel bears meeting at random in infinity d_labes 2010-04-22 11:43 [🇷 for BE/BA]
- Parallel bears meeting at random in infinity ElMaestro 2010-04-22 12:53
  - Parallel groups in bear - CIs d_labes 2010-04-22 14:00
    - Parallel groups in bear - CIs ElMaestro 2010-04-22 21:47
      - Parallel groups in bear - CIs d_labes 2010-04-23 09:09
    - Parallel groups in bear - CIs yjlee168 2010-04-25 23:29
- Parallel bears meeting at random in infinity yjlee168 2010-04-22 23:09
  - Modelling Parallel bears d_labes 2010-04-23 09:12
    - Modelling Parallel bears yjlee168 2010-04-23 21:14
      - Validating vs. WinNonlin... Helmut 2010-04-24 00:28
        
        Validating vs. WinNonlin... yjlee168 2010-04-24 19:36
        Validating vs. WinNonlin... yjlee168 2010-04-26 00:09
        
        Validating vs. WinNonlin... Helmut 2010-04-26 01:29
        
        WNL in replicate BE yjlee168 2010-04-26 08:59
        
        WNL in replicate BE Helmut 2010-04-26 16:15
      - Modelling Parallel bears yjlee168 2010-04-25 19:34
        
        Modelling Parallel bears ElMaestro 2010-04-25 20:40
        Dataset Helmut 2010-04-25 22:38
        
        Dataset yjlee168 2010-04-25 22:44
        
        Dataset Helmut 2010-04-26 01:13
        
        Dataset yjlee168 2010-04-26 08:16
        
        NCA → Statistical analysis for parallel study Helmut 2010-04-26 13:12
        
        NCA → Statistical analysis for parallel study yjlee168 2010-04-26 18:43
        
        dilemma yjlee168 2010-04-26 08:41
        Equal variances d_labes 2010-04-26 09:04
        
        Equal variances yjlee168 2010-04-26 09:22
        
        GLM = Equal variances d_labes 2010-04-26 13:29
        
        GLM = Equal variances Helmut 2010-04-26 14:45
        
        I'm a believer d_labes 2010-04-26 15:58
        
        I'm a believer Helmut 2010-04-26 16:31
        
        Equal variances Helmut 2010-04-26 12:55
        
        gls() for unequal variances? d_labes 2010-04-26 16:36
        
        gls() for unequal variances? Helmut 2010-04-26 17:00
        SimsHelmut 2010-04-27 01:36
        
        Sandwich - Simsalabim d_labes 2010-04-28 10:58
        
        Sandwich - Simsalabim Helmut 2010-04-28 14:19
        parametrization of R function rlnorm martin 2010-05-02 18:22
        
        Mean of log-normal d_labes 2010-05-03 16:22
        parametrization of R function rlnorm ElMaestro 2013-07-26 21:42
        
        Martin‽ Helmut 2013-07-28 02:01