Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer
 
PerlMonks  

Re: Birthday Chances

by ehdonhon (Curate)
on Feb 15, 2002 at 23:17 UTC ( #145788=note: print w/replies, xml ) Need Help??


in reply to Birthday Chances

The question here is: What are the chances of any n people not having unique birthdays? That's a difficult question. But the cool thing about probability is that you can always find the probability of something by subtracting the probability of its inverse from one. So instead, ask: What are the chances of any n people having unique birthdays? That would be:

(1/365) * ( 1/365 -1) * (1 /365 -2 ) * ... ( 1/365 - (n-1))

And once you have that, the answer to the original question is:

1 - ( (1/365) * ( 1/365 - 1 ) * ( 1/365 - 2) * ... ( 1/365 - (n-1)))

Now just plug in different values of n to find the odds of n people not having unique birthdays.

Replies are listed 'Best First'.
Re: Re: Birthday Chances
by Merlin42 (Friar) on Feb 18, 2002 at 14:36 UTC
    You might want to adjust your parenthization(is that a word?) ;)
    I think what you really want is:
    1 - ( 1/365 * 1/(365 - 1) * 1/(365 - 2) * ... * 1/(365 - (n-1)) )

    Kevin

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://145788]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others cooling their heels in the Monastery: (4)
As of 2022-08-10 17:16 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?