QUESTION 21 In a quality control test, & samples, each having four plates, were selected and the thickness of each plate in each sample was measured. The measurements in millimeters are given in the following Table. Calculate UCL and LCL for X- bar and sample plate 1 plate 2 plate 3 plate 4 number thickness thickness thickness thickness Average Maximum Minimum Range 47 50 50 41 2 38 47 43 43 3 46 14 43 46 4 48 42 47 47 5 47 47 38 45 6 48 40 47 48 7 41 46 39 40 8 46 37 45 43 Total Total Calculate the values in the last four columns and answer the questions What is the total value of the average column (e. the sixth column in the cable) QUESTION 22 Refer to the Problem in question 21 What is the value of the grand mean or the process mean or mean of means, denoted by X? (Note: It is also called X-double bar) QUESTION 23 Refer to the Problem in question 21 What is the total value of the range column (the last column in the table) ? QUESTION 24 Refer to the Problem in question 21 What is the mean value of the range, R ? (Note: It is also called R-bar) QUESTION 25 What is the value of A2? (Read the value from the Chart) QUESTION 26 What is the value of D4? (Read the value from the Chart) QUESTION 27 Refer to the problem in question 21. What is the Upper Control Limit, UCL(X)