The Birthday Parodox

[spacelem]

Given a room of 23 people, there is roughly a 50% chance that two of them will have the same birthday.

Tomorrow (Tuesday the 19th) is my 25th birthday. It is also lyandar's, and probably a large number of other peoples' birthdays worldwide.

I intend to celebrate this with drinks and a party at my flat (118 Lauriston place, the road between Tollcross and

Comments

[lucyjin]

D'OH!!

I have an engagement of priorness. >_<;; I'm really sorry, I can't make it. :( Hope it goes good though. *glomp*

[thrashgrrrl]

Grr sorry I can't make it. The roads are pretty bad here and Steve's car hasn't been working 100%. I can't afford the train through:( Hope you have a really good time though!

[two_truths]

Why 23 people instead of 24 people?

[spacelem]

Well, the probability you are looking for is:

P(n people in room don't share a birthday) = 365!/[365n(365-n)!]

And it just happens that this is closest to 0.5 when n=23.

[_ladyp_]

Happy birthday!

[black_agnes]

Harry Ruairidh, Frodo Somerled and Eblis O'Shaughnessy are busy wrapping presents. Unfortunately HR has swigged the bottle of Bundaberg O.P.