An agency collects demographics concerning the number of people in families per household in a certain country. Assume the distribution of the number of people per household is as shown in the table to the right.

a.

Calculate the expected number of people in families per household in the country.

b.

Compute the standard deviation of the number of people in families per household.

x P(x)

2 0.27

3 0.26

4 0.26

5 0.15

6 0.05

7 0.01