According to the Census Bureau publication Current Population Reports, the probability distribution for household size (number of people per household, say X) in the United States is as follows. For the purpose of the next two questions, the experiment consists of randomly selecting a household in the United States and observing the number of people living there.
x 1 2 3 4 5 6 7
P(X = x) 0.16 0.32 0.05 0.31 0.10 0.05 0.01
How many people can we expect to see living in the randomly chosen household?
Answer
4.14
3.06
4.00
1.79
1.24
What is the probability that the randomly selected household will contain more than 4 people?
Answer
0.47
0.31
0.16
0.84
0.53
2 answers