Thanks to Kit Baum, a new version of the -bpmedian- package is now available for download from SSC. In Stata, use the -ssc- command to do this, or the -adoupdate- command if you already have the old version of -bpmedian-.
The -bpmedian- package is described as below on my website. The new version fixes 2 bugs, which sometimes caused -bpmedian- to calculate the wrong median, or a missing variance estimate, when the number of observations was small and/or odd. These bugs seem to be fixed, according to my certification program, which I have also expanded as part of this update. I have also added an additional saved result e(c), containing the rank of the original upper confidence limit used to calculate the Bonett-Price standard error (which is an example of an inverse confidence interval standard error).
I would like to thank Ariel Linden for very helpfully alerting me to these hazardous bugs, and to apologize for any users who have been inconvenienced by them.
Best wishes
Roger
Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [email protected]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/
Opinions expressed are those of the author, not of the institution.
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package bpmedian from http://www.imperial.ac.uk/nhli/r.newson/stata10
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TITLE
bpmedian: Bonett-Price confidence intervals for medians and their contrasts
DESCRIPTION/AUTHOR(S)
bpmedian calculates a Bonett-Price confidence interval for a median,
using the Bonett-Price standard error, and saves the results as
estimation results. These can then be saved in an output dataset (or
resultsset), using the parmest package (downloadable from SSC), and
then input to the metaparm module of the parmest package to calculate
Bonett-Price confidence intervals for a linear contrast between
medians of independent groups. bpdifmed calculates Bonett-Price
confidence intervals for the medians of two groups, defined by a
grouping variable, and also for their difference or ratio.
Author: Roger Newson
Distribution-Date: 05june2009
Stata-Version: 10
INSTALLATION FILES (click here to install)
bpmedian.ado
bpdifmed.ado
bpmedian.sthlp
bpdifmed.sthlp
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