MEPX
Chapter 11 of 11All chapters
  1. 1What probability means
  2. 2Counting outcomes
  3. 3Independent events
  4. 4Dependent events
  5. 5Complements and at least one
  6. 6Adding probabilities
  7. 7Permutations and combinations
  8. 8Conditional probability
  9. 9Expected value
  10. 10Distributions in outline
  11. 11Fallacies and traps

Chapter 11 of 11

Fallacies and traps

Where intuition goes wrong.

The gambler's fallacy

Five heads in a row does not make tails due. Each flip is independent, so the next is still an even chance, and expecting a correction is the classic error.

  • Past results only matter if they suggest the coin is not fair.
  • The hot hand is the same mistake with the sign flipped.

Rare things happen often

A one in a million event happens to seven thousand people a day worldwide. Coincidences feel meaningful because we notice the hits and never count the misses.