Bioequivalence and Bioavailability Forum

Answering an unasked question [RSABE / ABEL]

posted by Helmut – Vienna, Austria, 2015-07-02 15:03 (3450 d 21:14 ago) – Posting: # 15016
Views: 30,043

Dear Detlew!

❝ Sometimes it would be helpful to RTFM :-D .

Oh, I did. You will note that I hacked your code of CVp2CV() for my function sep2s(). :-D

❝ Note that the ratio is here the ratio of variances.

Exactly. But I was interested in the ratio of standard errors instead.

library(PowerTOST) sep2s <- function(CV, ratio=1) { sp <- CV2mse(CV) swt <- sqrt(2)*sqrt(sp)*ratio/sqrt(ratio^2+1) swr <- sqrt(2)*sqrt(sp)/sqrt(ratio^2+1) r <- se2CV(c(swt, swr)) return(r) } CV <- 0.07 ratio <- 2 r1 <- CVp2CV(CV=CV, ratio=ratio) mse1 <- CV2mse(r1) se1 <- CV2se(r1) r2 <- sep2s(CV=CV, ratio=ratio) mse2 <- CV2mse(r2) se2 <- CV2se(r2) cat("Function CVp2CV()\n", "CV", CV, "split based on the variance ratio:", signif(r1, 3), "\n", "variances:", signif(mse1, 3), "ratio:", signif(mse1[1]/mse1[2], 3), "\n", "standard errors:", signif(se1, 3), "ratio:", signif(se1[1]/se1[2], 3), "\nFunction sep2s()\n", "CV", CV, "split based on the SE ratio:", signif(r2, 3), "\n", "variances:", signif(mse2, 3), "ratio:", signif(mse2[1]/mse2[2], 3), "\n", "standard errors:", signif(se1, 3), "ratio:", signif(se2[1]/se2[2], 3), "\n")

Which gives:

Function CVp2CV() CV 0.07 split based on the variance ratio: 0.0809 0.0571 variances: 0.00652 0.00326 ratio: 2 standard errors: 0.0807 0.0571 ratio: 1.41 Function sep2s() CV 0.07 split based on the SE ratio: 0.0886 0.0442 variances: 0.00782 0.00196 ratio: 4 standard errors: 0.0807 0.0571 ratio: 2

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Complete thread:

3 period full replicate Dr_Dan 2015-06-24 13:55 [RSABE / ABEL]
- 3 period full replicate ElMaestro 2015-06-24 14:11
- 3 period full replicate Helmut 2015-06-24 14:29
- 3 period full replicate d_labes 2015-06-24 14:38
  - 3 period full replicate Dr_Dan 2015-06-24 16:43
    - 3 period full replicate Helmut 2015-06-24 18:00
      - 3 period full replicate ElMaestro 2015-06-24 18:11
        
        3 period full replicate Helmut 2015-06-24 18:25
        
        3 period full replicate d_labes 2015-06-25 08:52
        
        3 period full replicate ElMaestro 2015-06-25 10:37
        
        OT d_labes 2015-06-25 11:20
        
        OT ElMaestro 2015-06-25 11:54
        
        OT d_labes 2015-06-25 13:51
    - CVs (borderline OT) Helmut 2015-06-26 13:51
      - CVs (R, T) from pooled CV d_labes 2015-07-02 09:09
        
        Answering an unasked questionHelmut 2015-07-02 13:03
        
        Answer to an unasked answer d_labes 2015-07-02 14:21
        
        Bloody typo! Helmut 2015-07-02 14:33
      - CVs (borderline OT) zizou 2015-07-05 19:20
        
        Degrees of freedom 3-period full replicate d_labes 2015-07-06 11:10
        
        Degrees of freedom 3-period full replicate ElMaestro 2015-07-06 11:59
        
        Degrees of freedom 3-period full replicate d_labes 2015-07-06 13:53
        
        Degrees of freedom 3-period full replicate zizou 2015-07-06 17:25
- The almighty oracle has spoken! Helmut 2015-07-23 23:54
  - Almighty oracle's mysterious saying d_labes 2015-07-24 08:23

Answering an un­asked ques­tion [RSABE / ABEL]

Complete thread:

Answering an unasked question [RSABE / ABEL]