The U.S. Census Bureau (Annual Social & Economic Supplement) collects demographics concerning the number of people in families per household. Assume the distribution of the number of people per household is shown in the following table:
| x |
P(x) |
| 2 |
0.27 |
| 3 |
0.25 |
| 4 |
0.28 |
| 5 |
0.13 |
| 6 |
0.04 |
| 7 |
0.03 |
a. Compute the variance and standard deviation of the number of people in families per household.
b. Calculate the expected number of people in families per household in the United States.