It is possible to get confidence limits corresponding to the -ranksum-
test. If �scar wants a confidence interval for the -porder- parameter, then
one possibility is to use the -somersd- package, downloadable from SSC. If
this is installed, then you can type
somersd control series, tr(c)
and -somersd- will print out a confidence interval for the -porder-
parameter. The -somersd- package can also produce confidence limits for
Somers' D.
If �scar wants a confidence interval for the median difference between
controlled and uncontrolled values of -series-, then this can be done with
the program -cendif- (part of the -somersd- package). To do this, type
cendif series, by(control)
The -somersd- package can calculate a wide range of other confidence
intervals for rank statistics, and these are described in the .pdf manuals
distributed with -somersd-.
I hope this helps.
Roger
At 17:38 31/10/2005, Nick Cox wrote (in reply to �scar Becerra):
A t test springs to mind, provided that its assumptions
are reasonably satisfied.
Plotting a graph springs even more to mind.
Nick
[email protected]
�scar Becerra-CERAC
> Thanks, and can anyone suggests to me a procedure to perform
> this test?
Richard Goldstein
> porder is taking all possible pairs (control=yes paired with
> each control=
> no) and asking in what percent of those pairs is No larger
> than YES; this
> does not appear to be the question you are asking; if I
> correctly understand
> your question, I think you want a parametric procedure rather than the
> rank-sum test
>
--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
Division of Asthma, Allergy and Lung Biology
King's College London
5th Floor, Capital House
42 Weston Street
London SE1 3QD
United Kingdom
Tel: 020 7848 6648 International +44 20 7848 6648
Fax: 020 7848 6620 International +44 20 7848 6620
or 020 7848 6605 International +44 20 7848 6605
Email: [email protected]
Website: http://phs.kcl.ac.uk/rogernewson/
Opinions expressed are those of the author, not the institution.
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