An irate customer called dollar day mail order company 40 times during the last two weeks to see why his order had not arrived. each time he called, he recorded the length of time he was put "on hold" before being allowed to talk to a customer service representative.

x = 1 2 3 4 5 6 7 8 9 10 11 12 13

f = 1 1 1 2 6 7 5 6 6 2 1 1 1

Assume the above data represents the entire population of people calling the dollar day mail order company.

a. Use the relative frequencies to find P(x) for x= 1 to 13

b. What is the probability that a customer selected at random had to wait more than 5 minutes?

c. What is the probability that a caller waited less than or equal to 4 minutes?

d. Compute the expected value of the x distribution.

e. Compute the standard deviation for the x distribution