In order to provide better service, a customer service call center investigated the hang-up rates of people who called in for help on a recent evening. These data were collected.

a. Make a table showing the probability distribution of the random variable x, where x represents the duration of the call in three-minute intervals.
b. Construct a relative frequency histogram for the probability distribution.
c. What is the median length of time a customer waited before hanging up?
d. Draw a smooth curve on your histogram, so that the area under the curve is approximately the same as the area of the histogram.

Hang-Up Rates Duration of call before hanging up (min) Number of customers 0-3 3-6 6-9 9-12 12-15 15-18 4 13 9 buration ot cal befo-2 1-42427 27-30 30-33 18-2121-2424-2727-30 30-33 hanging up (min) Number of customers 10 4