A television network plans to predict the outcome of an election between Candidate A and Candidate B.

They will do this with an exit poll on election day. They decide to use a random sample size for which the margin of error is 0.05 for 95% confidence intervals for population proportions.

(a) What sample size should they use?

(b) If the pollsters think that the election will be close, they might use a margin of error of 0.025.

How large should the sample size be?