Tuesday, 17 June 2014

Birthday Paradox At The World Cup

Many of you will be familiar with the Birthday Paradox and perhaps seen this article already, but the BBC recently used the 23 player World Cup squads as an excuse to look at it again.

Basically the birthday puzzle or paradox is that if we ignore February 29th, a group of 23 people has a greater than 50% chance of containing at least two people who share a birthday (month and day).

The BBC article also looks at the birth months of the squads, with some not totally surprising observations (in 1997, FIFA made 1 January the age cut-off for international soccer competitions):

For the 2014 World Cup players, the four months with the most birthdays are January (71), February (77), March (68) and May (72). These are all above the 61 birthdays a month you'd expect if they were evenly distributed.
And the months with the fewest birthdays all come in the second half of the year: August (57), October (46), November (49) and December (51).
An interesting read if you like your stats, and who doesn't?

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