Paying for music downloads. If you use the Internet, have you ever paid to access or...

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.”