1. The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first determine the percentage of adults who have heard of the brand. How many adults must he survey in order to be 95 confident that his estimate is within five percentage points of the true population percentage?

a) Assume that nothing is known about the percentage of adults who have heard of the brand. 2. A research institute poll asked respondents if they felt vulnerable to identity theft. In the poll,

n=1052 and x=579 who said "yes." Use a 95% confidence level.

a) Find the best point estimate of the population proportion p.

b) Identify the value of the margin of error E.

c) Construct the confidence interval.

3.A drug is used to help prevent blood clots in certain patients. In clinical trials, among

4863 patients treated with the drug, 127 developed the adverse reaction of nausea. Construct a

95% confidence interval for the proportion of adverse reactions.

a) Find the best point estimate of the population proportion p.

b) Identify the value of the margin of error E.

c) Construct the confidence interval.

4. In a study of cell phone use and brain hemispheric dominance, an Internet survey was e-mailed to 2321 subjects randomly selected from an online group involved with ears. 1107 surveys were returned. Construct a 95% confidence interval for the proportion of returned surveys.

a) Find the best point estimate of the population proportion p.

b) Identify the value of the margin of error E. c) Construct the confidence interval.