ACT Preparation / Unit 15 ACT 1428 short lesson, about 20 seconds
Expected Value
Captions available
The idea
The expected value is the long-run average outcome: multiply each outcome by its probability and add.
In practice
A game pays $10 with probability 0.2 and $0 otherwise: the expected value is 10 × 0.2 = $2 per play.
Where people slip
The expected value need not be a possible outcome; no single play pays $2. A cost to play subtracts from it.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
- Nothing yet depends on this.
Something wrong in this lesson? Flag it · Sources for ACT Preparation