American consumers comfortable using their credit cards to make purchases over the Internet? Suppose that a noted authority suggests that credit cards will be firmly established on the Internet once the "80 percent barrier" is broken; that is, as soon as more than 80 percent of those who make purchases over the Internet are willing to use a credit card to pay for their transactions. A recent Gallup Poll (story, survey results, and analysis can be found at www.gallup.com/poll/releases/ pr000223.asp) found that, out of n = 302 Internet purchasers surveyed, 267 have paid for Internet purchases using a credit card. Based on the results of the Gallup survey, is there sufficient evidence to conclude that the proportion of Internet purchasers willing to use a credit card now exceeds 0.80? Set up the appropriate null and alternative hypotheses, test at the 0.05 and 0.01 levels of significance, and calculate a p-value for your test.
Go to the Gallup Organization website (www. gallup.com). Select an interesting current poll and prepare a brief written summary of the poll or some aspect thereof. Include a statistical test for the significance of a proportion (you may have to make up your own value for the hypothesized proportion p0) as part of your report. For example, you might select a political poll and test whether a particular candidate is preferred by a majority of voters (p > 0.50).