Peer-to-peer music downloading. The NPD Group reported that the percent of Internet users who download music via peer-to-peer (P2P) services was 9% in late 2010, compared with 16% in late 2007.23 The filing of lawsuits by the recording industry may be a reason why this percent has decreased. Assume that the sample sizes are both 5549, the sample size reported for the 2010 survey.
Using a significance test, evaluate whether or not there has been a change in the percent of Internet users who download music via P2P services. Provide all details for the test and summarize your conclusion.
Also report a 95% confidence interval for the difference in proportions (2007 versus 2010) and explain what information is provided in the interval that is not given in the significance test results.