Question 8.58

27.Table 8.10 gives a probability model for total household income.

Table 8.23: Table 8.10 Probability Model of Total Income of U.S. Households (based on data from the March 2013 Supplement, Current Population Survey)
Total Household Income Probability
Under $25,000 0.174
$25,000 to $49,999 0.218
$50,000 to $74,999 0.185
$75,000 to $99,999 0.140
$100,000 or over 0.283

393

  1. Check to see whether the probability model in Table 8.10 is legitimate. Explain what you checked.
  2. What makes the probability model in Table 8.10 a discrete probability model?
  3. What is the probability that a randomly chosen household will have a total income less than $50,000?
  4. What is the probability that a randomly chosen household will have a total income less than $100,000?
  5. Suppose two U.S. households were randomly selected. What is the probability that both households will have a total income less than $100,000?

27.

(a) The probabilities were all between 0 and 1 inclusive, and the sum of the probabilities is 1. Hence, the probability model is legitimate.

(b) The model is discrete because there are only five possible categories for outcomes.

(c)

(d)

(e)

A-22