Forty-two cities provided information on vacancy rates (in percent) for local apartments in the following frequency distribution. Vacancy Rate (in percent)Frequency
0 up to 310
3 up to 69
6 up to 98
9 up to 127
12 up to 158
a. What is the average vacancy rate?
b. What is the variance?
c. What is the Standard Deviation?

Step-by-step explanation:

Given

Solving (a): The average vacancy rate

First, we calculate the class midpoint (x). This is the mean of the class boundaries.

When done for the whole class, the frequency table becomes:

The average rate is:

Solving (b): The variance

This is calculated as:

Solving (c): The standard deviation.

This is calculated as:

1.5%

step-by-step explanation:

10000

step-by-step explanation: divide by 2,