Question

An attendant at a car wash is paid according to the number of cars that pass through. Suppose the probabilities are 1/12, 1/12, 1/4, 1/4, 1/6, and 1/6, respectively, that the attendant receives $7, $9, $11, $13, $15, or $17 between 4:00 P.M . and 5:00 P.M . on any sunny Friday. Find the attendant’s expected earn- ings for this particular period.

Answer 1

Answer: The attendant’s expected earn- ings for the period between 4:00 P.M and 5:00 P.M is $12,67.

Explanation: The discrete random variable X represent attendant’s earnings.

The expected value of the discrete random variable X is

= E (x) = ∑× f(x)

= 7 × 1/12 + 9 × 1/12 + 11 × 1/4 + 13 × 1/4 + 15 × 1/6 + 17 × 1/6 = 12,67.