Pepsi Co. has installed a new automatic cola filling machine. Following samples were taken during the first week of production. The factory manager asked you to check if the dispersion of the process is in control. Which chart should you use?

Sample	Bottle 1	Bottle 2	Bottle 3
1	20.1	20.1	19.8
2	20	19.5	20
3	19.9	20.1	19.4
4	18	21.8	20.5
5	20	19.7	20

1. Which chart should you use?
2. What will be the upper and lower control limits, respectively?
3. Based on the analysis of dispersion, is the process in control?