compromised power [Power / Sample Size]
Hi Darya,
To keep everything equal you should convert the standard deviation to the CV. Hence,
Of course higher than the 28 by the dubious formula. As David mentioned above (quoting Zhang’s paper) power is compromised. Let’s check how much:
❝ The sample size by the formula I used:
❝ n=28
To keep everything equal you should convert the standard deviation to the CV. Hence,
library(PowerTOST)
sampleN.TOST(CV=se2CV(0.3))
+++++++++++ Equivalence test - TOST +++++++++++
Sample size estimation
-----------------------------------------------
Study design: 2x2 crossover
log-transformed data (multiplicative model)
alpha = 0.05, target power = 0.8
BE margins = 0.8 ... 1.25
True ratio = 0.95, CV = 0.3068783
Sample size (total)
n power
42 0.818541
Of course higher than the 28 by the dubious formula. As David mentioned above (quoting Zhang’s paper) power is compromised. Let’s check how much:
power.TOST(CV=se2CV(0.3), n=28)
[1] 0.6250166
—
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
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:
- sample size in bioequivalence studies daryazyatina 2017-08-03 09:34 [Power / Sample Size]
- sample size in bioequivalence studies BE-proff 2017-08-03 09:55
- sample size in bioequivalence studies daryazyatina 2017-08-03 10:08
- sample size in bioequivalence studies ElMaestro 2017-08-03 10:17
- sample size in bioequivalence studies daryazyatina 2017-08-03 10:58
- sample size in bioequivalence studies DavidManteigas 2017-08-03 12:40
- sample size in bioequivalence studies daryazyatina 2017-08-03 13:46
- Don’t use the formula by Chow, Shao, Wang! Helmut 2017-08-03 15:37
- Don’t use the formula by Chow, Shao, Wang! daryazyatina 2017-08-03 15:52
- Don’t use the formula by Chow, Shao, Wang! DavidManteigas 2017-08-03 16:12
- Don’t use the formula by Chow, Shao, Wang! Helmut 2017-08-03 16:33
- Don’t use the Book by Chow, Shao, Wang! d_labes 2017-08-16 16:01
- compromised powerHelmut 2017-08-03 16:04
- compromised power daryazyatina 2017-08-04 08:15
- terminology Helmut 2017-08-04 12:41
- terminology daryazyatina 2017-08-16 10:12
- terminology Helmut 2017-08-16 18:54
- terminology daryazyatina 2017-08-16 10:12
- terminology Helmut 2017-08-04 12:41
- compromised power daryazyatina 2017-08-04 08:15
- sample size in bioequivalence studies DavidManteigas 2017-08-03 12:40
- sample size in bioequivalence studies daryazyatina 2017-08-03 10:58
- sample size in bioequivalence studies balinskyi 2018-06-03 12:58
- sample size in bioequivalence studies BE-proff 2017-08-03 09:55