The manager of Champion Cooling Company has recently implemented a statistical process control method. The accompanying table shows the results of several different samples of walk-in coolers that were produced in the previous month.

For your reference, the A2 value for determining the three-sigma control limits is given below:

1) What is the value of the center line for the chart that monitors performance?

2) What is the value of the upper control limit and lower control limit?

3) Construct an x-bar chart using the data in the table. 15 the process in control?

Sample 1 Sample 2 Sample 3 Sample 4 100.1 101.1 102.0 104.4 100.4 105.9 103.6 103.0 104.6 101.4 101.0 102.1 100.7 104.9 107.0 Unit 1 104.0 Unit 2 106.4 Unit 3 101.8 Unit 4 105.6 Unit 5 100.6 n 3 4 5 6 A2 1.023 0.729 0.577 0.483