Refer to Exercises 8 and 9, and now employ control limits based on using the sample rang...

Refer to Exercises 8 and 9, and now employ control limits based on using the sample ranges to estimate σ. Does the process appear to be in control?

Reference Exercises 8

The table below gives data on moisture content for specimens of a certain type of fabric. Determine control limits for a chart with center line at height 13.00 based on σ = .600, construct the control chart, and comment on its appearance.

Reference Exercises 9

Refer to the data given in Exercise 8, and construct a control chart with an estimated center line and limits based on using the sample standard deviations to estimate σ. Is there any evidence that the process is out of control?