Paying for music downloads. If you use the Internet, have you ever paid to access or download music? This was one of the questions of interest in a recent Pew Internet and American Life Project Survey (Oct. 2010). Telephone interviews were conducted on a representative sample of 1,003 adults living in the United States. For this sample, 506 adults stated that they have paid to download music.

a. Use the survey information to find a point estimate for the true proportion of U.S. adults who have paid to download music.

b. Find an interval estimate for the proportion, part

a. Use a 90% confidence interval.

c. Give a practical interpretation of the interval, part

b. Your answer should begin with “We are 90% confident …”

d. Explain the meaning of the phrase “90% confident.”