In May of 2000, the Pew Research Foundation sampled 1593 respondents and asked how they obtain news. In Pew s report, 33% of respondents say that they now obtain news from the Internet at least once a week.
a) Pew reports a margin of error of for this result. Explain what the margin of error means.
b) Pew also asked about investment information, and 21% of respondents reported that the Internet is their main source of this information. When limited to the 780 respondents who identified themselves as investors, the percent who rely on the Internet rose to 28%. How would you expect the margin of error for this statistic to change in comparison with the margin of error for the percentage of all respondents?
c) When restricted to the 239 active traders in the sample, Pew reports that 45% rely on the Internet for investment information. Find a confidence interval for this statistic.
d) How does the margin of error for your confidence interval compare with the values in parts a and b? Explain why.