[R] birthday problem (factorial limit)

[Bernardo Rangel Tura]

Em Dom, 2008-09-28 às 19:43 +0200, Jörg Groß escreveu:
> Hi,
> 
> I tried to calculate the formula for the birthday problem
> (the probability that at least two people out of a group of n people  
> share the same birthday)
> 
> But the factorial-function allows me only to calculate factorials up  
> to 170.
> 
> 
> So is there a way to push that limit?
> 
> to solve this formula:
> 
> (factorial(365) / factorial((365-23))) / (365^23)
> 
> (n=23)

Log experession

n<-23
exp(sum(log(1:365))-sum(log(1:(365-n)))-n*log(365))

[1] 0.4927028


-- 
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil