Roll a number cube. If the number cube comes up odd, you win the same number of points as the number on the cube. If the number comes up even, you lose 4 points.What is the expected number of points per roll?

The six equally likely outcomes give point changes of +1, −4, +3, −4, +5, and −4. Their average is (1 − 4 + 3 − 4 + 5 − 4) ÷ 6 = −3 ÷ 6 = −0.5 points, so the expected number of points is −0.5 (choice B).

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