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How important is? may be less than 80 and why?
Regards,
BERNARDINO SILVA
UNIDADE DE AVALIACAO DE ESTUDOS DE BIODISPONIBILIDADE E
BIOEQUIVALENCIA DE MEDICAMENTOS / UABBE
GERENCIA GERAL DE MEDICAMENTOS - GGMED
AGENCIA NACIONAL DE VIGILANCIA SANITARIA - ANVISA
MINISTERIO DA SAUDE- MS
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The following message was posted to: PharmPK
Dear Bernardino!
You wrote:
> How important is? may be less than 80 and why?
>
See these two posts:
http://forum.bebac.at/mix_entry.php?id=1798#p1801
http://forum.bebac.at/mix_entry.php?id=2324#p2338
And this paper:
J.M. Hoenig and D.M. Heisey
The Abuse of Power: The Pervasive Fallacy of Power Calculations
for Data Analysis
The American Statistician 55/1, 19 24 (2001)
http://www.vims.edu/fish/faculty/pdfs/hoenig2.pdf
In short:
Power of less than 70% in sample size calculations (a priori)
may rise ethical question (unnecessary treatment of subjects with
lower than 30% change to demonstrate BE), whereas more than 90%
may look like one is trying to 'force bioequivalence'.
Calculation of posteriori power is a flawed concept and does not
make sense at all.
Regards,
Helmut
--
Ing. Helmut Schuetz
BEBAC - Consultancy Services for
Bioequivalence and Bioavailability Studies
Neubaugasse 36/11
1070 Vienna, Austria
e-mail helmut.schuetz.aaa.bebac.at
web http://bebac.at/
contact http://bebac.at/Contact.htm
forum http://forum.bebac.at
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