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.