A school administrator is concerned about the amount of credit-card debt that college students have. She wishes to conduct a poll to estimate the percentage of full-time college students who have credit-card debt of $2000 or more. What size sample should be obtained if she wishes the estimate to be within 2.5 percentage points with 94% conﬁdence if
(a) A pilot study indicates that the percentage is 34%?
(b) No prior estimates are used?