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For Exercises 4.90 and 4.91, see page 212; for 4.92, see page 214; and for 4.93, see page 216.

Question 4.91

4.91 How many cars?

Choose an American household at random and let the random variable be the number of cars (including SUVs and light trucks) they own. Here is the probability model if we ignore the few households that own more than five cars:

Number of cars 0 1 2 3 4 5
Probability 0.09 0.36 0.35 0.13 0.05 0.02
  1. Verify that this is a legitimate discrete distribution. Display the distribution in a probability histogram.
  2. Say in words what the event is. Find .
  3. Your company builds houses with two-car garages. What percent of households have more cars than the garage can hold?

4.91

(a) It is a legitimate discrete distribution. (b) The American household owns at least one car. (c) 20%.