The Manager of the Service Department of a Local Car

Multiple Choice

The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a standard deviation of 4 minutes.A 95% confidence interval estimate for the variance of service times for all their new automobiles is

A) 8.576 to 39.794.
B) 9.46 to 34.09.
C) 2.144 to 9.948.
D) 2.93 to 6.31.