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-   -   The Birthday Paradox (https://www.cpfc.org/forums/showthread.php?t=273620)

Finbar 02-07-2018 12:12 AM

That is awesome work, exactly 50% :)

It seems incredible to have 4 on the same day. Like spinning 365 number roulette wheel 25 times and getting the same number 4 times. Though thinking of it like that I can see that it could be 50/50 to get 1 repetition in those 25 spins

CommercialStone 24-08-2018 11:15 AM

Quote:

Originally Posted by hughff (Post 14047653)
Haven't opened the link but IIRC it's about 25-30. Then at about a 95% chance it's around 40

Of course to have a 100% chance you need at least 367 people - one for each day of the year plus one more.

Still not 100% though.....

NorthernEagle80 24-08-2018 11:31 AM

Not totally relevant but my girlfriend shares a birthday with her Dad and I share one with my Nephew. I would have thought that would be pretty long odds. My Niece is also only 2 days from my Sister.

switchboard 24-08-2018 11:36 AM

Quote:

Originally Posted by ExiledStirling (Post 14047685)
Has anyone actually tested this out for real?

I get the logic but still struggle to see that if in reality if you grouped together a number of times 23 people that reality will match the logic used.

Can't we simply prove or disprove this with how many posters it takes to find someone who shares our birthday?

I'll start if anyone wants to join

24th May

Finbar 24-08-2018 11:41 AM

Well I think the World Cup squad link above proves it in real life quite well

Anyway, 3rd June

Funk Butter 24-08-2018 01:11 PM

Quote:

Originally Posted by CommercialStone (Post 14399621)
Still not 100% though.....

Are you using something other than the Gregorian calendar?

David of Kent 24-08-2018 01:15 PM

Our office has 32 people in it with 2 pairs of identical birthdays.

Away 24-08-2018 05:27 PM

Quote:

Originally Posted by Funk Butter (Post 14399763)
Are you using something other than the Gregorian calendar?


Didn't read the question properly.

palacemetros 24-08-2018 08:49 PM

Quote:

Originally Posted by Finbar (Post 14399651)
Well I think the World Cup squad link above proves it in real life quite well

Anyway, 3rd June

Mrs Palacemetros is 3rd June!

25th October

Funk Butter 25-08-2018 02:51 AM

For those of you going to the match tomorrow, here's something you can do while you wait for kickoff. (Btw, he mentions my birthday in the video. There has to be something like a .54% chance of that happening)


Funk Butter 29-05-2019 10:41 PM

Since we have another World Cup coming up, I decided to check out some birthdays. Of the 24 teams playing in the Women's World Cup coming up, 11 have players that share the same birthday. Brazil is the only country with more than one duplicate birthday with two. There are two Brazilians and two Chileans that were born on December 17th.

Throughout the whole tournament, there are three players born on 12/17/1993 and 10/2/1992. There are 28 other instances of two players having the same exact birthday (including year).

https://en.wikipedia.org/wiki/2019_F...rld_Cup_squads

Am Phibian 29-05-2019 10:51 PM

3 of us had the same birthday in junior school class and 2 in my senior school one. 45 boys and 4 of us born on the same day.

Funk Butter 30-05-2019 03:12 PM

For extra completeness, I checked out the birthdays for the squads in the U-20 World Cup. Of the 24 of those teams, 12 had players with the same birthday. Norway, Poland, Senegal and the US had two pairs of players with the same birthday while Portugal had three sets.

Funk Butter 11-06-2021 05:56 AM

Another tournament and I've checked to see how many teams have players with matching birthdays. This time, teams are allowed to select up to 26 players for the tourney. As a result, this tournament has 18 of the 24 teams with multiple players with the same birthday. North Macedonia and Poland have 4 sets of players with the same birthday. England and Turkey have 3 sets. In fact, there is one team that not only has three players that share the same birthday but those players all play for the same club team. Bit of trivia for you to guess.

Finbar 11-06-2021 06:11 AM

Top statting FB, still find this maths hard to believe

wedgetail 11-06-2021 07:44 AM

Humans have bad intuitions regarding statistics, on average.

EdMan 11-06-2021 07:49 AM

Quote:

Originally Posted by hughff (Post 14047653)
Haven't opened the link but IIRC it's about 25-30. Then at about a 95% chance it's around 40

Of course to have a 100% chance you need at least 367 people - one for each day of the year plus one more.

I'm not sure that having 367 people in a room guarantees that at least two of them will have the same birthday. :angel:

Wolfnipplechips 11-06-2021 08:08 AM

Quote:

Originally Posted by Funk Butter (Post 14316321)
Since I didn't see an article related to the birthday stats of this year's World Cup squads, I did it myself. Of the 32 teams, 16 have two players with the same birthday. Poland takes the title with 4 sets of players with the same birthday. (all different ages, though) Portugal has three sets of players and Morocco and Brazil have two sets of players with the same birthday.

In other news; the long winter nights must fly by. :):p

jf63 11-06-2021 11:12 PM

My wife has a sister born on her birthday 5 years later and another sister that shares my sisters birthday, if this helps

El Aguila 11-06-2021 11:29 PM

This thread is missing Antoine Griezmann.


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