Six samples of subgroup size 7 ( n = 7) were collected. Determine the upper control limit (UCL) for an X-bar chart if the mean of the sample averages...

Six samples of subgroup size 7 (n = 7) 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

 7             0.419    0             1.924