Question: In June 2008, SBRI Public Affairs conducted a telephone poll of 1004 adult Americans aged 18 and older. One of the questions asked was, "In the past year, was there ever a time when you?" Respondents could choose more than one of the answers mentioned. Of the respondents, 64% said "cut back on vacations or entertainment because of their cost," 37% said "failed to pay a bill on time," and 25% said "have not gone to a doctor because of the cost." (Source: http://www.srbi.com/AmericansConcernEconomic.html.) Using these results, find a 95% confidence interval for the corresponding population percentage for each answer. Write a one-page report to present these results to a group of college students who have not taken statistics. Your report should answer questions such as:

(1) What is a confidence interval?

(2) Why is a range of values more informative than a single percentage?

(3) What does 95% confidence mean in this context?

(4) What assumptions, if any, are you making when you construct each confidence interval?