The Background
In probability theory, the birthday problem asks for the probability that, in a set of n randomly chosen people, at least two will share the same birthday. The birthday paradox is the counterintuitive fact that only 23 people are needed for that probability to exceed 50%.
To illustrate this seemingly counterintuitive statistical problem, this project pulls together a naturally occuring group of 23 individuals through international rugby fixtures to be able to demonstrate this using real groups of people. With 23 individuals the given probablity of their being at least one matching pair should be 50.7%.