A container of motor oil is supposed to contain 1000 mL of oil.A quality control engineer is concerned about the variability of the filling process.She randomly selects 10 containers.The number of mL in each container is given below:

983.6	1038.9	995.2	989.2	980.5
999.6	974.5	1035.8	945.7	983.3

(Assume that all criteria for constructing the confidence interval has beenmet.)

a)Construct a95% confidence interval for the population standard deviation of the number of mL's in each container of motor oil.

b)Interpret the 95% confidence interval.

c)The quality control engineer wants the filling process to have a population standard deviation below 20 mL. Does the confidence interval validate her desire? Explain why or why not.