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Samples of 12-volt batteries are taken at 30 minute intervals during a production run. Each sample c

Question: Samples of 12-volt batteries are taken at 30 minute intervals during a production run. Each sample consists of 3 batteries, and a technician records how long each battery will produce 400 amperes during a standard test. Given the data below, construct 3-sigma mean and range control charts and evaluate whether the process is in control.

Minutes, Battery Number

Sample Number 1 2 3

1 13.3 9.4 12.1

2 12.2 13.4 8.5

3 11.2 8.2 9.2

4 7.8 9.7 10.0

5 10.1 11.4 13.8

6 9.9 11.7 8.5

Minutes	or	Sample	Battery1	Battery2	Battery3
13.3		1	13.3	9.4	12.1
9.4		2	12.2	13.4	8.5
12.1		3	11.2	8.2	9.2
12.2		4	7.8	9.7	10.0
13.4		5	10.1	11.4	13.8
8.5		6	9.9	11.7	8.5
11.2
8.2
9.2
7.8
9.7
10.0
10.1
11.4
13.8
9.9
11.7
8.5