Which is the correct?

A.0.58

B.0.73

C.0.82

D.0.25

A quality manager is going to construct control charts for the samples shown below. What value of A2 should he/she use? Item 1 Item 2 Item 3 Item 4 Item 5 Mean Sample 1 2. 3 4 5 6 7 0.92 0.98 0.85 0.92 0.75 0.96 0.82 0.95 0.97 0.79 0.99 0.82 0.73 0.9 0.4 0.89 0.73 0.94 0.75 0.93 0.76 0.84 0.61 0.7 0.83 0.89 0.77 0.94 0.84 0.43 0.89 0.87 0.81 0.59 0.89 0.85 0.8 0.88 0.86 0.65 0.83 0.87 0.82 0.95 8 0.88 0.73 0.9 0.89 0.62 0.78 0.83 0.85 0.81 0.72 0.78 0.76 0.8 0.63 0.99 Range 0.09 0.25 0.17 0.33 0.31 0.2 0.1 0.34 0.27 0.18 0.21 0.2 0.97 0.94 0.77 0.68 0.93 0.83 0.74 0.89 0.79 0.76 0.92 0.67 0.81 0.94 0.8 Average: 0.91 0.85 0.85 0.77 0.82 0.84 0.81 0.84 0.83 0.75 0.88 0.78 0.82 0.85 0.69 0.82 9 10 11 12 13 14 15 0.21 0.32 0.59 0.25 0.85