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st: RE: Power calculation for McNemar's test
I think a possible solution to Eamonn's problem might be to use my
-powercal- and -somersd- packages, both downloadable from SSC. See
Newson (2002) and Newson (2004), which can both be downloaded in
pre-print form from my website from within Stata by typing
net from http://www.kcl-phs.org.uk/rogernewson/papers/
and proceeding from there. The present version of -somersd- can handle
paired data.
I hope this helps.
Best wishes
Roger
References
Newson R. Parameters behind "nonparametric" statistics: Kendall's tau,
Somers' D and median differences. The Stata Journal 2002; 2 (1): 45-64.
Newson R. Generalized power calculations for generalized linear models
and more. The Stata Journal 2004; 4(4): 379-401.
Roger Newson
Lecturer in Medical Statistics
POSTAL ADDRESS:
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute at Imperial College London
St Mary's Campus
Norfolk Place
London W2 1PG
STREET ADDRESS:
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute at Imperial College London
47 Praed Street
Paddington
London W1 1NR
TELEPHONE: (+44) 020 7594 0939
FAX: (+44) 020 7594 0942
EMAIL: [email protected]
WEBSITE: http://www.kcl-phs.org.uk/rogernewson/
Opinions expressed are those of the author, not of the institution.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Eamonn
O'Brien
Sent: 26 January 2006 11:44
To: [email protected]
Subject: st: Power calculation for McNemar's test
Hi
I am looking for some help with regard to power calculation using
McNemar's test.
I have 2 staining methods 'standard' and 'new' for reading slides. I
have a population consisting of 90 'routine' slides and 20 'abnormal'
slides which will be screened by 35 screeners using both stains. I wish
to be able to detect a 5% difference in the routine slides and 10%
difference in the 'abnormal'. Does Stata have a routine for this
calculation? As my sample size is fixed I am interested in what are the
power and significance level scenarios that I can obtain for this
experiment?
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* http://www.ats.ucla.edu/stat/stata/
