Different age groups use different media sources for news. A study on this issue explored the use of cell phones for accessing news. The study reported that 47% of users under age 50 and 15% of users age 50 and over accessed news on their cell phones. (Data extracted from "Cellphone Users Who Access News on Their Phones," USA Today, March 1, 2010, p. 1A.) Suppose that the survey consisted of 1,000 users under age 50, of whom 470 accessed news on their cell phones, and 891 users age 50 and over, of whom 134 accessed news on their cell phones.
a. Construct a 2 × 2 contingency table.
b. Is there evidence of a significant difference in the proportion that accessed the news on their cell phones between users under age 50 and users 50 years and older? (Use α = 0.05).