Refer to

Table S6.1 - Factors for Computing Control Chart Limits (3 sigma)

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for this problem.

Twelve samples, each containing five parts, were taken from a process that produces steel rods at Emmanual Kodzi's factory. The length of each rod in the samples was determined. The results were tabulated and sample means and ranges were computed. The results were:

Sample	Sample Mean (in.)	Range (in.)	Sample	Sample Mean (in.)	Range (in.)
1	12.704	0.044	7	12.703	0.021
2	12.704	0.051	8	12.703	0.058
3	12.693	0.042	9	12.693	0.039
4	12.708	0.037	10	12.701	0.038
5	12.699	0.048	11	12.701	0.054
6	12.701	0.053	12	12.708	0.061

Part 2

For the given data, the

x

=

enter your response here

inches (round your response to four decimal places).