Nielsen/NetRatings is a global leader in Internet media and market research. In a recent year, the firm reported on the "search" shares (i.e., percentage of all Internet searches) for the most popular search engines available on the Web. Google accounted for 50% of all searches, Yahoo! for 22%, MSN for 11%, and all other search engines for 17%. Suppose that in a random sample of 1,000 recent Internet searches, 487 used Google, 245 used Yahoo!, 121 used MSN, and 147 used another search engine.
a. Do the sample data disagree with the percentages reported by Nielsen/NetRatings? Test using α = .05.
b. Find and interpret a 95% confidence interval for the percentage of all Internet searches that use the Google search engine.