Question: A marketing executive wants to survey a city to determine how many people have purchased his company's product over the past twelve months.
(a) Suppose he wants a 95% confidence level in the results of the survey with an error of no more than 2%. How many people should he survey?
(b) How many people should he survey if, in (a), he is willing to allow the error to be no more than 5%?
(c) Suppose, in the previous year's study, it was found that, p¯ = 0.37. Now make an estimate of how many people he should survey for a 95% confidence level and an error of no more than 2%.
(d) Suppose another person in marketing notes an economic trend suggesting that a better estimate for, is 0.32. How will this affect the conclusion of (c) about the number of people to be surveyed?