To estimate the portion of voters who plan to vote for Candidate A in an election, a random sample of size n from the voters is chosen. The sampling is done with replacement. Let θ be the portion of voters who plan to vote for Candidate A among all voters.

a. How large does n need to be so that we can obtain a 90% confidence interval with 3% margin of error?

b. How large does n need to be so that we can obtain a 99% confidence interval with 3% margin of error?