Birthday Paradox

From Weekly I/O#32


Birthday Paradox: How many people do we need to have a 50-50 chance of at least two people sharing the same birthday? Only 23.

Article: The Birthday Paradox Experiment

Counterintuitively, in a room of only 23 people, the probability of at least two people sharing the same birthday is over 50 percent. Also, it only needs 60 people in a group to make sure that there’s a 99% chance of at least people having the same birthday. You can look up Wikipedia for a more detailed explanation or The Pudding to learn through an interactive experiment.

Thanks to Professor Juels for teaching this interesting paradox and Angelica Kosasih for sharing The Pudding website.


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