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C2: Ep. 41 - The Birthday Problem | DND404
13 October 2026

C2: Ep. 41 - The Birthday Problem | DND404

DND404 | Dungeons and Dragons Podcast

About

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%.

The birthday paradox is a veridical paradox: it seems wrong at first glance but is, in fact, true. While it may seem surprising that only 23 individuals are required to reach a 50% probability of a shared birthday (the number being less than 1/15th of the number of days in a year), this result is made more intuitive by considering that the birthday comparisons will be made between every possible pair of individuals. With 23 individuals, there are (23×22)/2=253 pairs to consider.

Real-world applications for the birthday problem include a cryptographic attack called the birthday attack, which uses this probabilistic model to reduce the complexity of finding a collision for a hash function, as well as calculating the approximate risk of a hash collision existing within the hashes of a given size of population.

The problem is generally attributed to Harold Davenport in about 1927, though he did not publish it at the time. Davenport did not claim to be its discoverer "because he could not believe that it had not been stated earlier". The first publication of a version of the birthday problem was by Richard von Mises in 1939.


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CAST:

Dungeon Master - Tony

Boram DuMarais - Dan

Kaz'il Amberleaf - Alec

Myelin Vaaxon - Jared

Vivien Charmant - Kyleigh

POST PRODUCTION:

Episode Director - Tony

Music - Dan

SFX - Tony

Intro theme "The Heartland" by Arcane Anthems