The Awake Coffee Company produces gourmet instant coffee. The company wants to be sure that the average fill of coffee containers is 12.0 ounces. To make sure the process is in control, a worker periodically selects at random a box of six containers of coffee and measures their weight. When the process is in control, the range of the weight of coffee samples averages 0.5 ounces.

a. Develop an R-chart and an x̄-chart for this process.

b. The measurements of weight from the last five samples taken of the six containers follow:

Sample x̅ R 1 12.0 0.6 2 11.2 0.5 3 12.7 0.5 4 11.3 0.4 5 11.7 0.8 Is the process in control? Explain your answer.