Library›Chance & Paradoxes›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaProbability or paradox

This probability-weighted average describes a random quantity's long-run mean.

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new ahaExpected Value

Expected Value: Used to evaluate whether a bet or decision is favorable. Source: Expected value ↗

ahamoraReference ↗

Keep the thread going

One answer is a beginning.

Share a little curiosity, or follow it into the full collection.

Flip the full deck →

More from Chance & Paradoxes

A few more worth knowing.

  1. 06This fallacy treats an independent losing streak as evidence that a win is now due.RECALL
    The Gambler's Fallacy

    The gambler's fallacy wrongly assumes past results affect future independent odds, expecting a losing streak to end.

    Open this card ↗
  2. 07This theorem updates a probability using prior beliefs and new evidence.RECALL
    Bayes' Theorem

    Bayes' theorem updates event probabilities as new evidence arrives, used from medical testing to spam filters.

    Open this card ↗
  3. 08In this three-door game-show puzzle, switching wins with probability 2/3 when an informed host always reveals a goat and offers a switch.RECALL
    The Monty Hall Problem

    The Monty Hall problem shows that switching doors, though counterintuitive, actually improves your odds of winning.

    Open this card ↗