Economic/Social
St. Petersburg Paradox
A game with infinite expected value that no one would pay much to play
Overview
A probability paradox showing expected value doesn't always match intuitive value.
A casino offers: flip a fair coin repeatedly until tails. You win $2^n where n is the number of flips. Expected value is infinite (sum of 1/2×$2 + 1/4×$4 + 1/8×$8...), yet no rational person would pay even $1000 to play. Why?