Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $30,000and$50,000. Assume that a95%confidence interval estimate of the population mean annual starting salary is desired.

a. What is the planning value for the population standard deviation?

b. How large a sample should be taken if the desired margin of error is $300? Round your answer to next whole number.

$250?

$70?

c. Would you recommend trying to obtain the $70 margin of error? Explain.