# st: RE: RE: product function

 From "Nick Cox" To Subject st: RE: RE: product function Date Tue, 25 May 2004 18:00:04 +0100

Woops. Sorry, Professor Feller!

. set obs 50
. gen i = _n
. gen double p = 1 - 1/365
. replace p = p[_n - 1] * (1 - _n / 365) in 2/l
. replace p = 1 - p
. scatter p i

Nick
n.j.cox@durham.ac.uk

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox
> Sent: 25 May 2004 17:56
> To: statalist@hsphsun2.harvard.edu
> Subject: st: RE: product function
>
>
> You don't need a built-in. This is one way of doing it.
>
> . set obs 50
> . gen i = _n
> . gen double p = 1 - 1/365
> . replace p = p[_n - 1] * (1 - _n / 365) in 2/l
> . scatter p i
>
> Nick
> n.j.cox@durham.ac.uk
>
> > -----Original Message-----
> > From: owner-statalist@hsphsun2.harvard.edu
> > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of
> Dimitriy V.
> > Masterov
> > Sent: 25 May 2004 17:43
> > To: statalist@hsphsun2.harvard.edu
> > Subject: st: product function
> >
> >
> > 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.
> >
> > DVM
> >
> >
> > ______________________________________________________________
> > _________________
> > Dimitriy V. Masterov
> >
> > Work:
> > Center for Social Program Evaluation
> > 1155 East 60th St. Room 038
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> >
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> >
> >
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