Practice Expected Value in Statistics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The long-run average outcome of a random process, calculated as the sum of each outcome times its probability.

If you played a game forever, expected value is your average result per play. Positive EV = profitable long-term. Negative EV = you'll lose over time. It's the mathematical way to evaluate risky decisions.

Example 1

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A game costs \2 to play. You roll a fair die: if you roll a 6, you win \10; otherwise, you win nothing. Find the expected value per game.

Example 2

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A raffle sells 200 tickets at \5 each. There is one prize of \500. Find the expected value for a ticket buyer.

Example 3

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A spinner has outcomes: \1 (prob 0.5), \3 (prob 0.3), \$10 (prob 0.2). Find the expected value.

Example 4

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A game costs \4 to play. You win \20 with probability 0.1, \5 with probability 0.3, and \0 otherwise. Find the expected net value of one play.
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