Harlene tosses two number cubes. If a sum of 8 or 12 comes up, she gets 9 points. If not, she loses 2 points. What is the expected value of the number of points for one roll?
P(8 or 12) = 1/6 P(not 8 or 12 = 5/6 Let the expected points fro one roll be X. [tex]E(X)=9\times\frac{1}{6}-2\times\frac{5}{6}=-\frac{1}{6}\ points[/tex] The answer is -(1/6) points.
