07-06. Measure theory and probability - Symmetric probability spaces: the birthday paradox.

This video is concerned with the very popular birthday problem: The probability that two people share the same birthday in a group of only 23 people is larger than one-half. Not only we give a proof of this result, we also prove that, looking at the number of pairs of people instead of the number of people, the answer is in fact not at all counter-intuitive, showing that the birthday “paradox” is not a paradox. This is Exercise 1.10 of my Stochastic Modeling book.