ELi5: what’s the birthday paradox ? And is its mathematical basics a correct proof?
In: Mathematics
It’s not really a paradox. It just goes against human intuition.
It comes from the that if there are 23 people in a room, there is ~50% chance two of them have a birthday in common. Most people would guess the number would be much higher.
It only takes 23 people because the number of pairs of people grows quadratically i.e. if you have *n* people in a room, you can pair them up in n(n-1)/2 different ways, so you have that many chances for a match.
The wikipedia article shows how to calculate the exact probabilities involved: [https://en.wikipedia.org/wiki/Birthday_problem](https://en.wikipedia.org/wiki/Birthday_problem)
Latest Answers