The fill procedure for nine-ounces bottles of Island Sunscreen Lotion is under scrutiny by a procedure improvement team. Sample averages and ranges from twenty samples of 4-bottles each are shown in the table given below. Construct X and R charts and determine if the process is in control or out of control.
Sample Average Ranges Sample Average Range
1 9.025 0.2 11 9.025 0.3
2 9.050 0.1 12 9.100 0.2
3 9.100 0.3 13 9.125 0.3
4 9.100 0.3 14 9.150 0.5
5 9.000 0.5 15 8.950 0.2
6 9.025 0.3 16 9.000 0.5
7 9.050 0.4 17 9.025 0.2
8 9.075 0.1 18 9.100 0.2
9 9.000 0.2 19 9.050 0.1
10 8.975 0.3 20 9.075 0.4