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 1 2 3 4 5.8 6.2 6.1 6.0 5.9 6.0 5.9 5.9 6.0 5.9 6.0 5.9 6.1 5.9 5.8 6.1