Asample containing years to maturity and yield for 40 corporate bonds is contained in the excel online file below. construct a spreadsheet to answer the following questions. open spreadsheet a. what is the sample mean years to maturity for corporate bonds and what is the sample standard deviation? mean (to 4 decimals) standard deviation (to 4 decimals) b. develop a 95% confidence interval for the population mean years to maturity. round the answer to four decimal places. ( , ) years c. what is the sample mean yield on corporate bonds and what is the sample standard deviation? mean (to 4 decimals) standard deviation (to 4 decimals) d. develop a 95% confidence interval for the population mean yield on corporate bonds. round the answer to four decimal places. ( , ) %