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RegisterParallel study in WinNonlin [Software]
posted by Helmut 
– Vienna, Austria, 2009-10-10 12:51 (5674 d 07:02 ago) – Posting: # 4338
Views: 27,267
Dear Yuvraj!
You are right about the pooled variance and the formula.
But WinNonlin's method (assuming equal variances) is flawed – even in the recent version of Phoenix/WinNonlin 6.0. For details see this thread.
FDA mandates a t-test corrected for unequal variances in their guideline. Although the conventional t-test is quite robust against violations of this assumption, it is sensitive if the dataset is imbalanced (which is regularly the case in parallel studies). Applying the wrong test will be anticonservative, i.e., the patient’s risk is inflated to an unknown degree. For an extreme example see one of my lectures (slides 65-68).
❝ MSE obtained from parallel study is pooled MSE.
❝ means Intra + Inter subject residual variance.
❝ […] one value obtained from WinNonlin (Final variance parameter workbook).
❝ Is it right, Sir?
You are right about the pooled variance and the formula.
But WinNonlin's method (assuming equal variances) is flawed – even in the recent version of Phoenix/WinNonlin 6.0. For details see this thread.
FDA mandates a t-test corrected for unequal variances in their guideline. Although the conventional t-test is quite robust against violations of this assumption, it is sensitive if the dataset is imbalanced (which is regularly the case in parallel studies). Applying the wrong test will be anticonservative, i.e., the patient’s risk is inflated to an unknown degree. For an extreme example see one of my lectures (slides 65-68).
—
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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. 🚮
Science Quotes
Complete thread:
- Sample Size Calculation sasikumar 2008-04-03 09:19
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Sample Size Calculation (SAS) Jaime_R 2008-04-03 13:13
- Sample Size Calculation d_labes 2008-04-23 11:54
- Sample Size Calculation balakotu 2009-09-07 07:51
- Sample Size Calculation yuvrajkatkar 2009-09-19 09:24
- Paper, pencil, brain ;-) Helmut 2009-09-19 11:48
- Paper, pencil, brain ;-) yuvrajkatkar 2009-09-21 15:10
- Paper, pencil, brain ;-) Helmut 2009-09-21 15:23
- Paper, pencil, brain ;-) Helmut 2009-09-21 18:33
- Paper, pencil, brain ;-) yuvrajkatkar 2009-09-22 16:09
- No paper, pencil, brain :-( Helmut 2009-09-22 18:22
- about your lectures yuvrajkatkar 2009-09-23 07:27
- About Trust Helmut 2009-09-23 13:50
- sample size calculation yuvrajkatkar 2009-10-01 13:33
- inter- / intra- / total variance Helmut 2009-10-01 13:52
- inter- / intra- / total variance yuvrajkatkar 2009-10-01 17:13
- Theta?! Helmut 2009-10-01 17:30
- sample size for parallel design yuvrajkatkar 2009-10-03 07:44
- Reference? Helmut 2009-10-03 13:46
- MSE obtain from Parallel study in WinNonlin yuvrajkatkar 2009-10-09 16:46
- Parallel study in WinNonlinHelmut 2009-10-10 10:51
- MSE obtain from Parallel study in WinNonlin yuvrajkatkar 2009-10-09 16:46
- Reference? Helmut 2009-10-03 13:46
- sample size for parallel design yuvrajkatkar 2009-10-03 07:44
- Theta?! Helmut 2009-10-01 17:30
- inter- / intra- / total variance yuvrajkatkar 2009-10-01 17:13
- inter- / intra- / total variance Helmut 2009-10-01 13:52
- sample size calculation yuvrajkatkar 2009-10-01 13:33
- About Trust Helmut 2009-09-23 13:50
- about your lectures yuvrajkatkar 2009-09-23 07:27
- No paper, pencil, brain :-( Helmut 2009-09-22 18:22
- Paper, pencil, brain ;-) yuvrajkatkar 2009-09-22 16:09
- Paper, pencil, brain ;-) yuvrajkatkar 2009-09-21 15:10
- Paper, pencil, brain ;-) Helmut 2009-09-19 11:48
Ing. Helmut Schütz