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.

x P(x)

2 0.27

3 0.27

4 0.28

5 0.11

6 0.03

7 0.04

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.