A quality control manager at a manufacturing facility

has taken four samples with four observations each of

the diameter of a part.

(a) Compute the mean of each sample.

(b) Compute an estimate of the mean and standard

deviation of the sampling distribution.

(c) Develop control limits for 3 standard deviations of

the product diameter.

Samples of Part Diameter in Inches

Samples of Part Diameter in Inches

1 2 3 4

5.9 6.3 6.3 6.2

5.7 5.8 6.3 5.8

5.8 5.8 6.2 5.9

6.1 6.0 6.3 5.7