these answers are wrong please help

Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $20,000 and $40,000 Assume that a 95% 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. $190? $130? c. Would you recommend trying to obtain the $130 margin of error? Explain. No, the sample size would probably be too time consuming and costly. Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $20,000 and $40,000 - Assume that a 95% 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. $190? $130? c. Would you recommend trying to obtain the $130 margin of error? Explain. Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $20,000 and $40,000 Assume that a 95% 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. $190? $130? c. Would you recommend trying to obtain the $130 margin of error? Explain. No, the sample size would probably be too time consuming and costly. Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $20,000 and $40,000 - Assume that a 95% 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. $190? $130? c. Would you recommend trying to obtain the $130 margin of error? Explain