EXAMPLE 10Expected value of a discrete random variable

Find the expected value of the following discrete random variables:

  1. in Example 3
  2. awarded in Example 5
  3. in Example 7

319

Solution

  1. Using the probabilities in Table 1, we have

    The expected number of heads is 1.

  2. Using Table 2, we have

    The expected number of points is 1.74.

  3. From Example 7, . The expected number of credits is 15.

NOW YOU CAN DO

Exercises 45c–52c.