Birthday Paradox

This is a very interesting idea that I saw from the internet, and was again reintroduced to after reading the Competitive Programmer’s Handbook.

The birthday paradox states that if there are people in a room, the probability that some two people have the same birthday is large even if is quite small.

The explanation for this is that the days at which people are born is not uniformly distributed. A lot of people are born during certain days of the year.

Pasted image 20220401041630.png In probability theory, the birthday problem asks for the probability that, in a set of randomly chosen people, at least two will share a birthday. The birthday paradox is that, counterintuitively, the probability of a shared birthday exceeds 50% in a group of only 23 people.