A survey by the AARP (Money, June 2007) reported that approximately 70% of people in the 50 to 64 age bracket have tried some type of alternative therapy (for instance, acupuncture or the use of nutrition supplements). Assume this survey was based on a sample of 400 people.
Compute the point estimate as well as the margin of error with 90% confidence. (Round intermediate calculations to 4 decimal places, "z" value and "point estimate" to 2 places, and "margin of error" to 3 decimal places.)
You decide to redo the analysis with the margin of error reduced to 2%. How large a sample do you need to draw? (Round intermediate calculations to 4 decimal places and "z" value to 2 decimal places. Round up your answer to the nearest whole number.)