Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $30,000 and $45,000. Assume that a 95% confidence interval estimate of the population mean annual starting salary is desired. What is the planning value for the population standard deviation? How large a sample should be taken if the margin of error is a. $500? b. $200? c. $100? d. would you recommend trying to obtain the $100 margin of error? Explain.