I need the steps

(A) In a sample of 12 men the quantity of hemoglobin in the blood stream had a mean of 15 g/dl and a standard deviation of 3 g/dl. Find the 99% confidence interval for the population mean blood hemoglobin. (Round your final answers to the nearest hundredth) B) A financial officer for a company wants to estimate the percent of accounts receivable that are overdue. He surveys 500 accounts and finds that 350 are overdue. Find a 95% confidence interval for the proportion of all accounts receivable that are overdue. (Round your final answers to the nearest hundredth) (C) Interpret the results (the intervals) you got in both the scenario given above (A and B)