PowerTOST: CVfromCI [Study Assessment]
❝ Dear Helmut,
▲ Not interested in other members’ opinions?
❝ If i found an article of a BABE study in which 3 formulation where evaluated against to reference (A) in a 4 way crossover study, …
So far, so good.
❝ … but in a bioequivalence table appears for example A vs B treatment and its respective Geometric Mean Ratio (IC 90%).
Being A the reference, it should be B vs A, right?
❝ If i wanna calculate CV% intrasubject ussing POWER.TOST which desing i have to pick up (4x4 or parallel)? Of course 4x4 is the real design but the comparative A vs B is technically a parallel study.
Parallel‽
You have to find out whether the study was evaluated with a “pooled ANOVA” or according to the “Two‐at‐a‐Time Principle” (see this post).
Example: 4×4 crossover, n 24, 90% CI 85.00–106.18%.
#############################################
n <- 24 # total sample size
l <- 0.8500 # lower 90% CL
u <- 1.0618 # upper 90% CL
#############################################
library(PowerTOST)
des <- "4x4" # design and 1st evaluation
eval <- "2x2" # 2nd evaluation
pe <- sqrt(l*u) # calculate the PE
CV.1 <- CVfromCI(lower=l, upper=u, design=des, n=n) # 1
CV.2 <- CVfromCI(lower=l, upper=u, design=eval, n=n) # 2
cat(paste0("\n", des, " design, n = ", n,
sprintf("%s %.2f%%%s", "\n90% CI =", 100*l, "\u2013"),
sprintf("%.2f%%", 100*u),
sprintf(" %s %.2f%%)", "(PE =", 100*pe),
sprintf("\n Pooled ANOVA : CVintra = %.2f%%",
100*CV.1),
sprintf("\n Two-at-a-Time Principle: CVintra = %.2f%%",
100*CV.2)), "\n")
4x4 design, n = 24
90% CI = 85.00%–106.18% (PE = 95.00%)
Pooled ANOVA : CVintra = 23.41%
Two-at-a-Time Principle: CVintra = 22.73%
How to discover which method was used?
Work backwards,
res.1 <- CI.BE(pe=pe, CV=CV.1, n=n, design=des)
res.2 <- CI.BE(pe=pe, CV=CV.2, n=n, design=eval)
cat(paste0("\nBack-calculated 90% CI by",
"\n Pooled ANOVA : ",
sprintf("%.2f%%%s", 100*res.1[["lower"]], "\u2013"),
sprintf("%.2f%%", 100*res.1[["upper"]]),
"\n Two-at-a-Time Principle: ",
sprintf("%.2f%%%s", 100*res.2[["lower"]], "\u2013"),
sprintf("%.2f%%", 100*res.2[["upper"]]), "\n"))
Back-calculated 90% CI by
Pooled ANOVA : 85.00%–106.18%
Two-at-a-Time Principle: 85.00%–106.18%
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-20 12:31 [Study Assessment]
- CV values in BE studies: intra, or inter, or total? jag009 2018-01-20 19:18
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-20 21:10
- CV values in BE studies: intra, or inter, or total? jag009 2018-01-21 03:17
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-21 08:21
- CV values in BE studies: intra, or inter, or total? jag009 2018-01-21 03:17
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-20 21:10
- CV values in BE studies: intra, or inter, or total? Helmut 2018-01-21 17:33
- CV values in BE studies: intra, or inter, or total? ElMaestro 2018-01-21 18:17
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-27 09:57
- CV values in BE studies: intra, or inter, or total? Louis52 2018-02-07 20:22
- CV values in BE studies: intra, or inter, or total? Helmut 2018-02-07 20:31
- CV values in BE studies: intra, or inter, or total? Rosy 2019-02-19 18:33
- PowerTOST: CVfromCIHelmut 2019-02-20 13:00
- PowerTOST: CVfromCI -> CI.BE d_labes 2019-02-20 14:12
- PowerTOST: CVfromCI Rosy 2019-02-20 15:25
- type known.designs() in PowerTOST Helmut 2019-02-20 16:14
- type known.designs() in PowerTOST Rosy 2019-02-20 17:14
- type known.designs() in PowerTOST Helmut 2019-02-20 16:14
- PowerTOST: CVfromCIHelmut 2019-02-20 13:00
- CV values in BE studies: intra, or inter, or total? Rosy 2019-02-19 18:33
- CV values in BE studies: intra, or inter, or total? Helmut 2018-02-07 20:31
- CV values in BE studies: intra, or inter, or total? Louis52 2018-02-07 20:22
- CV values in BE studies: intra, or inter, or total? Elena777 2018-01-27 09:57
- CV values in BE studies: intra, or inter, or total? jag009 2018-01-20 19:18