Exercise 2.2-12 (3 points) Suppose that a school has 20 classes: 16 with 25 students in each, three with 100 students in each, and one with 300 students, for a total of 1000 students. (a) What is the average class size. (b) Select a student randomly out of the 1000 students. Let the random variable X equal the size to which this student belongs, and define the pmf of X. (c) Find E(X), the expected value of X. Does this answer surprise you?

Exercise 2.2-12 (3 points) Suppose that a school has 20 classes: 16 with 25 students in each, three with 100 students in each, and one with 300 students, for a total of 1000 students. (a) What is the average class size. (b) Select a student randomly out of the 1000 students. Let the random variable X equal the size to which this student belongs, and define the pmf of X. (c) Find E(X), the expected value of X. Does this answer surprise you