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 central tendency of the process is in control. What will be the upper and lower control limits, respectively?

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

a.) 2.37 and 0

b.) 20.05 and 19.85

c.) 2.65 and 0

d.) 21.07 and 18.78