Question - Six samples of subgroup size 4 (n = 4) were collected. Determine the upper control limit (UCL) for an X-bar chart if the mean of the sample averages is 4.7 and the mean of the sample ranges is 0.35.
Factors for calculating control limits
n            A2                 D3         D4
2            1.880             0            3.267
3            1.023             0            2.574
4            0.729             0            2.282
5            0.577             0            2.114
6            0.483             0            2.004