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Timeline for Birthday Problem for 3 people

Current License: CC BY-SA 3.0

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Apr 13, 2017 at 12:20 history edited CommunityBot
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Sep 7, 2013 at 4:55 comment added Thomas Interesting, I wonder how many people you need for four people to share a birthday with 50% probability. If we made a graph of the function f(n) of the number of people needed to be 50% sure that n people have the same birthday, what would it look like?
Sep 7, 2013 at 4:52 vote accept Thomas
Sep 6, 2013 at 9:27 history edited Caleb Stanford CC BY-SA 3.0
added update
Sep 6, 2013 at 9:12 comment added Caleb Stanford @Henry, Using this answer, I calculate the probably for 84 people to be $.464549...$. You're right; the approximation is further off than I thought. But it's still reasonably accurate.
Sep 6, 2013 at 7:38 comment added Henry I think that with $84$ people in a room, the probability of three people sharing a birthday seems to be lower than $0.47$ (and for $83$ people still lower)
Sep 6, 2013 at 6:21 comment added Thomas Ok, that makes more sense. I was thinking 46 was a bit small. Especially given that the probability for 30 people is less than 0.05.
Sep 6, 2013 at 6:11 comment added Caleb Stanford @Thomas There was an error in my algebra. I've fixed it now, but it's 83 people in stead of 46.
Sep 6, 2013 at 6:10 history edited Caleb Stanford CC BY-SA 3.0
Fixed algebra mistake
Sep 6, 2013 at 6:07 comment added Thomas Interesting that it is about double of the amount needed to ensure 50-50 for two people having the same birthday.
Sep 6, 2013 at 6:03 comment added Caleb Stanford This comment in particular: math.stackexchange.com/questions/25876/…
Sep 6, 2013 at 6:02 comment added Caleb Stanford @vantonio1992 check out Byron's answer in the linked question. $1/365^2$ is the chance of a given three people having the same birthday.
Sep 6, 2013 at 6:00 comment added vantonio1992 Shoudn't the probability be over $365^3$ instead of $365^2?$
Sep 6, 2013 at 5:58 history answered Caleb Stanford CC BY-SA 3.0