The Irony of Bayes

More than 250 years ago, the challenge of making predictions from small data weighed strongly on presbyterian minister Reverend Bayes of Tunbridge Wells, England.

Looking to the easily banal Raffles of the 18th Century England he wondered what one's chances of winning them were. If five tickets out of ten bought won, then the chances of a win were quite simply 50%. But what if one bought a single ticket and it came out the winner? Were the chances of winning the Raffle really a 100%? It sounded far too simplistic to our dear Reverend who balanced scholarly and theological interests almost all his life. Ordained like his father and a man of keen intellect he was elected to the Royal Society in 1742.

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