The Roper Organization conducted a poll in 1992 (Roper, 1992) in which one of the questions asked was whether or not the respondent had ever seen a ghost. Of the 1525 people in the 18- to 29-year-old age group, 212 said "yes."
a. What is the approximate margin of error that accompanies this result?
b. What is the interval that is 95% certain to contain the actual proportion of people in this age group who have seen a ghost?