Nielsen Media Research reported that the average American home watched more television in 2007 than in any previous season. From September 2006 to September 2007 (the official start and end of television season in the United States), the average time spent by U.S. households tuned into television was 8 hours and 14 minutes per day. This is 13.85% higher than 10 years ago, and the highest levels ever reported since television viewing was first measured by Nielsen Media Research in the 1950s. To determine if television viewing has changed in 2008, a sample (in minutes) similar to the following would be used:

494 533 597 530 577 514 466 416 403 625 562 448 592 567 564 537 370 627 416 511 750 661 570 579 494 533 549 583 610 423

a. Calculate the sample standard deviation and mean number of minutes spent viewing television.

b. Calculate a 95% confidence interval for the average number of minutes spent viewing television in 2008.

c. Would the results obtained in part b indicate that households viewed more television in 2008 than in 2007?