Better yet, if its NOT 20, what's the formula to find out how many it actually takes.
2007-06-24 03:01:13 · 5 answers · asked by cozmik_terra 2 in Science & Mathematics ➔ Mathematics
That is a statistical issue and not determined by a formula.
The minimum number of people required to be in a room to be CERTAIN there is at least two people in the room with the same birthday is 366.
2007-06-24 03:05:15 · answer #1 · answered by tabulator32 6 · 0⤊ 2⤋
I can't come up with that formula. What I can do is come up with a formula that show the chances that two people in the room do not have the same birthday. Subtract this from 100% and you will have a winner.
chance is p
n = number of people in pool.
p =365X364X363...(365-n+1)/365^n
2007-06-24 03:45:27 · answer #2 · answered by eric l 6 · 1⤊ 0⤋
What is the probability (P) that at least 2 people in a group of n people have the same birthday?
The probability is
P(n) = 1 - 365!/((365^n)(365 - n)!)
For n = 23, P(23) ≈ 0.507
.
2007-06-24 03:17:24 · answer #3 · answered by Robert L 7 · 1⤊ 0⤋
Ok, its is difficult I will say that it can not happen with the dates but chances are 100 percent for same month and 50 percent for year.
2007-06-24 03:05:15 · answer #4 · answered by Anonymous · 0⤊ 3⤋
Hmm.... i think its about permutation... well if it is about permutation here is the answer : 20P2 ( 20 elements taken 2 at a time...) is equals to 380.
>> hope it helps you... ^_^
2007-06-24 03:26:10 · answer #5 · answered by Sel 1 · 1⤊ 2⤋