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RegisterNo worries! [RSABE / ABEL]
posted by Helmut 
– Vienna, Austria, 2012-02-08 14:37 (5253 d 11:58 ago) – Posting: # 8077
Views: 24,157
Dear AB!
I’m not a friend of post-hoc power calculations, but your result is not surprising:
According to Endrényi & Tóthfalusi, Table A2 (see there), you would have needed only 25 subjects (50% CV, PE 1.00) to show BE with 90% power.
You should follow the protocol. See the GL Section 4.1.10:
❝ PE is 100 and the number of subjects completed in the study were 70, the resulting CI was well within 80-125 with ISCV of 47%.
❝ could i suspect something wrong went in analysis?
I’m not a friend of post-hoc power calculations, but your result is not surprising:
library(PowerTOST)
power.TOST(theta0=1.00, CV=0.47, n=70, design="2x2x4")
[1] 0.9872979According to Endrényi & Tóthfalusi, Table A2 (see there), you would have needed only 25 subjects (50% CV, PE 1.00) to show BE with 90% power.
❝ on the other hand if every thing was correct why do we need widening of CI?
You should follow the protocol. See the GL Section 4.1.10:
The request for widened interval must be prospectively specified in the protocol.
- If you did not intend to scale: The acceptance range remains at 80.00–125.00% and since your 90% CI is within ⇒ BE.
- If you intended to scale the widened AR is:
library(PowerTOST)
exp(-0.76*CV2se(0.47)); exp(+0.76*CV2se(0.47))
[1] 0.7121033
[1] 1.404291
Since your 90% CI is within 71.21–140.43% and the PE is within 80.00–125.00% ⇒ BE.
—
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Helmut Schütz
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Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz
The quality of responses received is directly proportional to the quality of the question asked. 🚮
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Complete thread:
- ISCV and CI AB 2012-02-08 08:21
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- ISCV and CI drgunasakaran1 2012-02-08 08:44
- Sample size feasible d_labes 2012-02-08 09:47
- Sample size feasible AB 2012-02-08 11:40
- No worries!Helmut 2012-02-08 13:37
- Sample size down! d_labes 2012-02-08 14:18
- World record? Helmut 2012-02-08 14:31
- Wow! d_labes 2012-02-08 16:16
- World record? jag009 2015-09-23 20:43
- Nope Helmut 2015-09-23 21:57
- World record? Helmut 2012-02-08 14:31
- Sample size feasible AB 2012-02-08 11:40
Ing. Helmut Schütz