Chapter 5, Problem 5.30E

In a CBS News poll conducted between December 17 and 22, 2009, asked a random sample of $n=563$ married adult Americans, “Would you say that your marriage with your spouse is better, worse or about the same as your parent’s marriage?” (http://www.pollingreport.com/life .htm, March 9, 2010). The percentages that selected each response follow:

Better: 55%

Worse: 3%

About the same: 41%

Unsure: 1%

1. What is the margin of error for this poll? Give your answer as both a proportion and a percentage.
2. What is a conservative 95% confidence interval for the population porportion that would have responded, “Better”? Give your answer for the population percentage as well.
3. Write a sentence or two interpreting the interval that you found in part (b).
4. Based on the interval you found in part (b), could you conclude that in December 2009 more than half of all married adult Americans thought that their own marriage was better than their parents’ marriage? Explain.