okey so the birthday paradox
i know that it states that within a random group of like 23 people that there is a 50 percent chance two pple will have the same birthday but idk if the number 23 is right ive check tons of pages n they r all different
i know its in the 20 but im not sure what number is right???
What is the real number????????
2007-11-27 09:28:30 · 8 answers · asked by Peach Mango 3 in Science & Mathematics ➔ Mathematics
Here is the calculation:
1 - 365P23/365^23 = 50.73%
2007-11-27 09:38:15 · answer #1 · answered by sahsjing 7 · 1⤊ 0⤋
the number is 23.
2007-11-27 09:32:21 · answer #2 · answered by Anonymous · 0⤊ 0⤋
23 is the number.
2007-11-27 09:32:05 · answer #3 · answered by ben e 7 · 0⤊ 0⤋
What is the probability that no one of 20 people share the same birthday?
The first person can have any date (365/365)
The second person can have any date except the first,s (364/365)
The third person... except first's and second's (363/365)
...
The 20th person... except any of the first 19 (346/365)
Probability that they are all different =
(365/365)(364/365)(363/365)...(347/365)(346/365) =
(365! / 345!) / (365^20) =
0.58856
Therefore, probability that at least one pair shares a birthday = 0.4114 (41.14%) not fifty
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I just set it up in Excel
column A begins (A1) as 365
cell A2 is =A1-1
column B begins (B1) with 1
cell B2 is =B1*A2/365
column C begins (C1) with 0
cell C2 is =1-B2
row number 2 (cells A2, B2 and C2) are copied and pasted into rows 3 to 60.
row n corresponds to having n people in the room.
row 23
23 people in room
probability that at least one pair shares (cell C23) is 0.5073
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20 41.14%
21 44.37%
22 47.57%
23 50.73%
24 53.83%
25 56.87 %
30 70.63%
40 89.12%
50 97.04%
60 99.41%
2007-11-27 09:52:27 · answer #4 · answered by Raymond 7 · 0⤊ 0⤋
.99726... Under wikipedia, you might want to look at the formula that allows you to calulate the probability of two persons having the same birthdays, something of that nature. Of course that after you have search for Birthday Paradox in the search box. As for your answer of how many people would have the same acccording to the Birthday Paradox that number can range from 1 to inifinity.
2007-11-27 11:00:26 · answer #5 · answered by Anonymous · 0⤊ 0⤋
23 is the magic number
2007-11-27 09:34:29 · answer #6 · answered by Walt C 3 · 0⤊ 0⤋
chances are it doesn't really matter what the number is so long as it's around the mid 20s.
2007-11-27 09:32:32 · answer #7 · answered by Anonymous · 0⤊ 0⤋
i'm pretty sure it is 23 ppl, that's what i've heard before
2007-11-27 09:31:11 · answer #8 · answered by mitell23 2 · 0⤊ 0⤋