Two Basic Rules of Probability · Exercise 12

After a mayor of a major Canadian city announced his plans to cut budget costs in late 2011, researchers polled 1,046 people to measure the mayor’s popularity. Everyone polled expressed either approval or disapproval. These are the results their poll produced:

• In early 2011, 60 percent of the population approved of the mayor's actions in office.
• In mid-2011, 57 percent of the population approved of his actions.
• In late 2011, the percentage of popular approval was measured at 42 percent.

(a) What is the sample size for this study?
(b) What proportion in the poll disapproved of the mayor, according to the results from late 2011?
(c) How many people polled responded that they approved of the mayor in late 2011?
(d) What is the probability that a person supported the mayor, based on the data collected in mid-2011?
(e) What is the probability that a person supported the mayor, based on the data collected in early 2011?

OpenStax, Statistics · §3.3 Two Basic Rules of Probability · Exercise 12