Sid Luka is the service manager for Brakes Unlimited, a franchise corporation that specializes in servicing automobile brakes. He wants to study the length of time required to replace the rear drum brakes of automobiles. A subgroup of 10 automobiles needing their brakes replaced was selected on each day for a period of 20 days. The subgroup times required (in hours) for this service were recorded and are presented in the file Brakes.
a. Sid has been trying to get the average time required to replace the rear drum brakes of an automobile to be under 1.65 hours. Use the data Sid has collected to determine if he has reached his goal.
b. Set up the appropriate control charts to determine if this process is under control.
c. Determine whether the process is under control. If the process is not under control, brainstorm suggestions that might help Sid bring it under control. What tools of quality might Sid find useful?