1. Under what conditions is it appropriate to use the normal approximation to the binomial distribution in constructing the confidence interval for the population proportion?
2. A pharmaceutical company found that 46% of 1000 U.S. adults surveyed knew neither their blood pressure nor their cholesterol level. Assuming the persons surveyed to be a simple random sample of U.S. adults, construct a 95% confidence interval for 7T 5 the population proportion of U.S. adults who would have given the same answer if a census had been taken instead of a survey.
3. An airline has surveyed a simple random sample of air travelers to find out whether they would be interested in paying a higher fare in order to have access to e-mail during their flight. Of the 400 travelers surveyed, 80 said e-mail access would be worth a slight extra cost. Construct a 95% confidence interval for the population proportion of air travelers who are in favor of the airline's e-mail idea.