A technician services mailing machines at companies in the Phoenix area. Depending on the type of malfunction, the service call can take , , , or hours. The different types of malfunctions occur at the same frequency. If required, round your answers to two decimal places.

a. Develop a probability distribution for the duration of a service call.
b. Draw a graph of the probability distribution.
c. Show that your probability distribution satisfies the conditions required for a discrete probability function.
d. What is the probability a service call will take three hours?
e. Aservice call has just come in, but the type of malfunction is unknown. It is 3:00 p. m. and service technicians usually get off at 5:00 p. m. What is the probability the service technician will have to work overtime to fix the machine today?