a. Determine the sample size required to estimate a population mean to within 10 units given that the population standard deviation is 50. A confidence level of 90% is judged to be appropriate. b....

a. Determine the sample size required to estimate a population mean to within 10 units given that the population standard deviation is 50. A confidence level of 90% is judged to be appropriate. b. Repeat part (a) changing the standard deviation to 100. c. Re-do part (a) using a 95% confidence level. d. Repeat part (a) wherein we wish to estimate the population mean to within 20 units.