What is the upper control limit? 

What is the center line ? 

What is the lower control limit ?

 

A quality inspector took six samples, each with twenty observations, of the weight of a bagging process, in pounds. The sample means and ranges are shown below. Sample 2 3 6 Mean 3.55 3.80 3.50 3.60 3.50 3.55 Range 0.55 0.75 0.55 0.51 0.55 0.65 Use this information to obtain a three-sigma control chart (z = 3) for the mean weight. Process standard deviation is 0.27. Use that control chart to answer the questions