A real estate agent conducted a survey of 200 landlords and asked how long their apartments remained vacant before a tenant was found. The results of the survey are shown in the table. The data are based on information obtained from the U.S. Census Bureau.

Duration of Vacancy ....Frequency

Less than 1 month .......42

1 to 2 months .......38

2 to 4 months .......45

4 to 6 months .......30

6 to 12 months .......24

1 to 2 years .......13

2 years or more ....... 8

(a) Construct a probability model for duration of vacancy.

(b) Is it unusual for an apartment to remain vacant for 2 years or more?

(c) Determine the probability that a randomly selected apartment is vacant for 1 to 4 months.

(d) Determine the probability that a randomly selected apartment is vacant for less than 2 years.