Fifty cities provided information on vacancy rates (in percent) in local apartments in the following frequency distribution.

Vacancy Rate (in percent) ....Frequency

0 up to 3 ........... 5

3 up to 6 ...........10

6 up to 9 ...........20

9 up to 12 ...........10

12 up to 15 ......... 5

a. Construct the corresponding relative frequency distribution, cumulative frequency distribution, and cumulative relative frequency distribution.

b. How many of the cities had a vacancy rate less than 12%? What percent of the cities had a vacancy rate of at least 6% but less than 9%? What percent of the cities had a vacancy rate of less than 9%?

c. Construct a histogram. Comment on the shape of the distribution.