Re: st: product function

 From Roger Newson To statalist@hsphsun2.harvard.edu Subject Re: st: product function Date Tue, 25 May 2004 18:06:01 +0100

At 11:43 25/05/04 -0500, Dimitriy V. Masterov wrote:

I would like to plot the probability that two people share a birthday as a
function of the number of people in the room n. The formula is

1-product((366-i)/365,i,1,n)

In TeX, it would be

1-\dprod\limits_{i=1}^{n}\frac{366-i}{365}.

If I have a variable n={1,...,50}, how can I define the product within
Stata? There does not seem to be math function that can do this.

One way might be to calculate logs and then to use the -sum()- function.

Roger

--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
King's College London
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Tel: 020 7848 6648 International +44 20 7848 6648
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Email: roger.newson@kcl.ac.uk
Website: http://www.kcl-phs.org.uk/rogernewson

Opinions expressed are those of the author, not the institution.

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