Quality control Crank shafts at the Ford motors plant in Detroit are produced in a melting process. The diameter is a critical factor that must be controlled. From samp produced each day, the mean and the range of this diameter have been as follows: Day Mean (mm) Range (mm) 1 156.9 4.2 2 153.2 4.6 3 153.6 4.1 4 155.5 5.0 5 156.6 4.5 You want to determine whether the process is in statistical control or not. Fill in the following information. Use 2 decimals everywhere, and a dot to separate the decimals from the rest (for example: 12.34). Answer the following questions. Include arguments and computations. X a) (4 points) Compute R and b) (4 points) Compute the lower and upper control limits of X and R c) (2 points) Is the process in statistical control? Why? Or why not?