Bioequivalence and Bioavailability Forum

Mea culpa! [Power / Sample Size]

posted by Helmut  – Vienna, Austria, 2020-05-04 12:40  – Posting: # 21395
Views: 4,166

Hi ElMaestro,

» the powerTOST package is excellent …

THX!

» … and I am not myself a very experienced user (yet) as I tend to rely on much less reliable code of my own making

Sure. In line what Jaime once stated:

Never trust in any piece of software you haven't written yourself
(and even then you should be cautious…)

» So forgive me I am asking: I think the OP implied a partial replicate. TRR/RRT/RTR is not 3x6x3 but rather 2(trts)x3(seqs)x3(pers), …

Oops! You are absolutely right.

» » 3 way crossover, reference replicate

» … is there a reason to plug in 3x6x3 in your code?

I screwed up! Of course, not a 3-period Williams’ design. Hence,

library(PowerTOST)
round(100 * CVfromCI(lower = 0.9625, upper = 1.2511,
                     n = 41, design = "2x3x3"), 2)

and

Unbalanced 2x3x3 design. n(i)= 14/14/13 assumed.
[1] 42.97

That’s reasonably close to the 42.6% given in the PAR. Sorry for the confusion caused!

@Alyssa: Can you please check whether the expanded limits are also given in the PAR? Based on CV_wR 42.6% they should be close to

round(100 * scABEL(CV = 42.6 / 100), 1)
lower upper
 73.3 136.4

—
Dif-tor heh smusma 🖖
Helmut Schütz


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

Complete thread:

• Sample size calculation (Pilot study result vs literature) Alyssa 2020-05-04 04:35 [Power / Sample Size] 
  • Sample size calculation (Pilot study result vs literature) Dr_Dan 2020-05-04 08:46
    • Sample size calculation (Pilot study result vs literature) Alyssa 2020-05-04 09:26
  • Estimation of CVw and/or CVwR Helmut 2020-05-04 12:07
    • Estimation of CVw and/or CVwR ElMaestro 2020-05-04 12:14
      • Mea culpa!Helmut 2020-05-04 12:40
        • It must be Myco ElMaestro 2020-05-04 13:46
          • It is, it is! Helmut 2020-05-04 14:07
            • It is.... Alyssa 2020-05-05 05:00
              • Tutorial Helmut 2020-05-05 12:45
                • Tutorial Alyssa 2020-05-08 06:48
                  • library d_labes 2020-05-08 11:16
                  • Tutorial (from the start) Helmut 2020-05-08 13:08
                    • Tutorial (from the start) Alyssa 2020-05-12 04:05
                      • Tracking down error Helmut 2020-05-12 11:49
                        • Tracking down error: stringsAsFactors d_labes 2020-05-13 11:34
                          • R <4.0.0 Helmut 2020-05-13 12:07
                            • R <4.0.0 ElMaestro 2020-05-13 14:18
                              • R <4.0.0 🔚 Helmut 2020-05-13 14:21
                            • PowerTOST’s functions with as.character(design) d_labes 2020-05-13 18:50
                              • PowerTOST’s functions with as.character(design) Helmut 2020-05-13 18:55
                        • Tracking down error Alyssa 2020-05-15 05:08
                          • All’s well that ends well. Helmut 2020-05-15 10:52