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bish
Doesn't have much of a life
Joined: Tue Apr 28, 2009 11:45 am
Posts: 732
Location: 'sup mah science bitchezz!?
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Fook Fermats theorum. Bastard! Haha!
_________________ I make full use of this action, while at x404.
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| Fri Oct 16, 2009 10:48 am |
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Zippy
Spends far too much time on here
Joined: Thu Apr 23, 2009 6:20 pm
Posts: 3838
Location: Here Abouts
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Depends how much of the thread is going to be taken up with "I'm right...here's why" arguments  I'm not pitting my numbers brain against the likes of JJ and Jon, I already know who'll come out best there  and the only reason I get on with numbers at all is that I have an afinity for statistics (lies and damned lies) but I will enjoy reading them. _________________The Official "Saucy Minx"  This above all: To Thine Own Self Be True "Red sky at night, Shepherds Delight"..Which is a bit like Shepherds Pie, but with whipped topping instead of mashed potato.
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| Fri Oct 16, 2009 10:55 am |
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jonlumb
Spends far too much time on here
Joined: Thu Apr 23, 2009 6:44 pm
Posts: 4141
Location: Exeter
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Ok, this is a bit of an old chestnut but here goes.
How many people do you need to have in a group before the odds of two of them sharing the same birthday is better than 50%?
_________________
"The woman is a riddle inside a mystery wrapped in an enigma I've had sex with."
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| Fri Oct 16, 2009 11:03 am |
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bish
Doesn't have much of a life
Joined: Tue Apr 28, 2009 11:45 am
Posts: 732
Location: 'sup mah science bitchezz!?
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22... I think. a slightly anal answer of 367? That is the only way to guarantee two share the same birthday based on there being 366 days in the longest year (leap years must be included as people can be born on the 28th Feb) and an extra person to share the birthday. Maybe? :s _________________ I make full use of this action, while at x404.
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| Fri Oct 16, 2009 11:07 am |
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jonlumb
Spends far too much time on here
Joined: Thu Apr 23, 2009 6:44 pm
Posts: 4141
Location: Exeter
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To guarantee, then yes you need 367, however, I'm simply after it being likely (ie greater than 50%)
22 is pretty close by the way. The issue is why it is so...
_________________
"The woman is a riddle inside a mystery wrapped in an enigma I've had sex with."
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| Fri Oct 16, 2009 11:12 am |
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EddArmitage
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 9:40 pm
Posts: 5288
Location: ln -s /London ~
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| Fri Oct 16, 2009 11:22 am |
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bish
Doesn't have much of a life
Joined: Tue Apr 28, 2009 11:45 am
Posts: 732
Location: 'sup mah science bitchezz!?
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Ah I give up. Anyone else want to have a go?  HAHAH! Edd that's brilliant. _________________ I make full use of this action, while at x404.
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| Fri Oct 16, 2009 11:23 am |
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Paul1965
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 8:29 pm
Posts: 5975
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I can see that this thread is going to be waaayyy over my head.  Still, I might learn something!
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"I hadn't known there were so many idiots in the world until I started using the Internet." - Stanislaw Lem
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| Fri Oct 16, 2009 11:35 am |
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Fogmeister
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 7:35 pm
Posts: 6580
Location: Getting there
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Well... 1 person in the room = 0 2 people = 1/366 3 people = 1/366 + 1/366 + 1/366 (i.e. the probablilty that A has the same as B OR B has the same as C OR A has the same as C) = 1/122 4 = ... n people = (1/366) x n!/(2(n-2)!) if 0.5 > (1/366) x n!/(2(n-2)!) then ... after some working out... 0 > n^2 - n - 366 so... 366 > n^2 -n (guessing values...) 19 < n < 20 for a probability of a half that 2 people share the same birthday.  Let's just call it 20 I wouldn't like to be in a room with 19 and a half people.
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| Fri Oct 16, 2009 11:39 am |
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Fogmeister
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 7:35 pm
Posts: 6580
Location: Getting there
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Apprently it's 23 (using 365 days).
Hmm...
I still get 20 but I was rushing.
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| Fri Oct 16, 2009 11:49 am |
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EddArmitage
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 9:40 pm
Posts: 5288
Location: ln -s /London ~
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Did you expect anything less of me??? (8-p)
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| Fri Oct 16, 2009 12:00 pm |
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jonlumb
Spends far too much time on here
Joined: Thu Apr 23, 2009 6:44 pm
Posts: 4141
Location: Exeter
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Some modesty perhaps?
_________________
"The woman is a riddle inside a mystery wrapped in an enigma I've had sex with."
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| Fri Oct 16, 2009 12:02 pm |
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EddArmitage
I haven't seen my friends in so long
Joined: Thu Apr 23, 2009 9:40 pm
Posts: 5288
Location: ln -s /London ~
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Oh I was being modest. I'm that good (8-p)
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| Fri Oct 16, 2009 12:06 pm |
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