The following table provides a probability distribution for the random variabley.

y f(y)

3 0.10

5 0.30

6 0.40

9 0.20

a.ComputeE(y)(to 1 decimal).

b.ComputeVar(y)and(to 2 decimals).

Var(y)

A technician services mailing machines at companies in the Phoenix area. Depending on the type of malfunction, the service call can take 1.1, 2.2, 3.2, or 4.3 hours. The different types of malfunctions occur at the same frequency.

Probability distribution for the duration of a service call.

duration of call

x f(x)

1.1

2.2

3.2

4.3

1. What is the probability a randomly selected service call will take 3.2 hours?
2. A service call has just come in, but the type of malfunction is unknown. It is 3:00P.M.and service technicians usually get off at 5:00P.M.What is the probability the service technician will have to work overtime to fix the machine today?