Question: Suppose that it is a presidential election year and Ohio is one of the “swing” states. Your polling company wants to conduct a presidential preference poll of the citizens of Ohio to predict which candidate will win the election.

a. How many voters must be polled to be 95% confident of your results within +/- 3%?

b. How many voters must be polled to be 95% confident of your results within +/- 2%?

c. How many voters must be polled to be 95% confident of your results within +/- 1%?

d. Discuss the effect of margin of error on sample size.