Yes, you could use -nptrend- to test for trend between 2 ordinal variables such as yours. However, -nptrend- only gives you a P-value. It might be more informative to have a confidence interval for a trend measure, such as Somers' D. To get this, use the -somersd- package, which you can download from SSC.
I hope this helps.
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.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Rune Nielsen
Sent: 23 July 2009 09:12
To: [email protected]
Subject: st: chi squared test for trend
Dear all!
I've tried searching the archives concerning this without finding it
explicitly.
I've got two categorical variables, one ordered with three groups, and
the other as an dichotomous outcome. Can I use the nptrend command to
test for trend of proportion over the three (ordered) groups?
Best wishes
Rune N.
---
Rune Nielsen, MD, research fellow
Institute of Medicine
Department of Thoracic Medicine
Haukeland University Hospital
N-5021 Bergen
Norway
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