Suppose you want to estimate the proportion of classmates who plan to spend their junior year abroad. You take a simple random sample of 100 classmates from a total class population of 3500. Twelve students in the sample indicate that they plan a junior year abroad.
a. Build a 95% interval estimate of the overall class proportion based on your sample findings.
b. Suppose you want to reduce the margin of error by 30% at the 95% confidence level. How big a sample size would be required?