Discuss the following:
Q: The mayor of a small town would like to know whether a local bond issue is likely to pass or not. He mails a survey to 500 randomly selected voters. How many returns must he get in order to know the proportion that will support the bond issue within an error of 5% and a confidence level of 95%? If he gets a 60% return from the mailing and would like to keep the error at 5%, what will happen to his confidence in the result? If he gets a 60% return from the mailing and would like to maintain his 95% confidence in the result, what will happen to the error?