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Hi all,
Potvin's method were developed for 2,2,2-BE crossover trials but I am interested in extending the methodology to parallel designs. In this regard I have two major areas of doubt:
Best regards and muchas gracias for any input you can give,
EM.
Notes:
Potvin's method were developed for 2,2,2-BE crossover trials but I am interested in extending the methodology to parallel designs. In this regard I have two major areas of doubt:
- I want to use the power formula that Potvin used, only with modification for the parallel situation. This is the formula that approximates power on basis of the central t-distribution. For technical reason (that means speed!) I am not going to us Owen's Q or shifted t. So what would the formula look like for the parallel case1? In particular please describe your interpretation of n and df for your answer, if possible. Let's assume equal variances for simplicity, so that s is a pooled st.dev. estimate.
- If we assume non-equal variances, what would the (or a) formula looks like then2?
Best regards and muchas gracias for any input you can give,
EM.
Notes:
- I tried to read Julious, C&L, and even the documentation for power.TOST but stil have my doubts.
- A less stringent solution at this step would be to simplify and assume equal variances for the powering step alone. This would then imply derivation of a pooled estimate of s which goes into the formula under question 1.
Complete thread:
- Parallel Power ProblemsElMaestro 2013-02-14 14:46
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Parallel Power shifted d_labes 2013-02-15 09:16
- Doubts explained ElMaestro 2013-02-15 11:37
- Parallel Power shifted d_labes 2013-02-15 09:16
Ing. Helmut Schütz