Exact methods can be used.
I once wrote a small DOS program to calculate such limits which I attach.
poisslim.exe (63kb)
to use in this example
press - 3 - Poisson limits then 8 0 [Enter] (n=8, r=0)
to get the answer probability p=0, 95% limits high 0.37 low 0.
ps the program will handle batch files and the C++ source file is available if wanted.
The help is terse and minimalistic.
Others may have better software.
Rory
ps I am afraid that I am unable to resend attachments if they are trashed by NHSnet or the Internet.
Dr Rory O'Conor
Consultant Clinical Epidemiologist
Clinical Audit
Pinderfields & Pontefract Hospitals NHS Trust
Wakefield WF1 4DG, UK
Tel: +44 1924 212850
Fax: +44 1924 814864
Email: [log in to unmask]
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o=nhs pinderfields and pontefract hospitals tr;
ou=gwise;s=oconor;g=rory"
http://nww.panp-tr.northy.nhs.uk/ (extranet)
http://www.demon.co.uk/pinderfields/ (internet)
http://www.btinternet.com/~rory.oconor/ (personal)
>>> DDA.RFC-822=evidence-based-health-request(a)mailbase.ac.uk 22/07/99 08:11 >>>
Can any one help? I'm struggling with the technical point of how to deal
with a proportion of zero,
especially in a small study. e.g. "none of the eight study patients
responded to treatment therefore the treatment
should never be used clinically for similar patients".
Is there a way of generating a confidence interval for a proportion of
zero?
