Nice write-up of The Birthday Paradox on the BBC today.
It’s puzzling but true that in any group of 23 people there is a 50% chance that two share a birthday.
Some bright spark noticed that, with exactly 23 players in each World Cup 2014 squad, here was a topical example with which to test the theory, by which at least half of the 32 squads are expected to have a shared birthday.
Using the birthdays from Fifa’s official squad lists as of Tuesday 10 June, it turns out there are indeed 16 teams with at least one shared birthday – 50% of the total.