Internet music, again. A Gallup Poll (Exercise 57)

asked Americans if the fact that they can make copies of songs on the Internet for free made them more likely—or less likely—to buy a performer’s CD. Only 13% responded that it made them “less likely.” The poll was based on a random sample of 703 Internet users.

a) Check that the assumptions and conditions are met for inference on proportions.

b) Find the 95% confidence interval for the true proportion of all U.S. Internet users who are “less likely” to buy CDs.