Piston rings for an automotive engine are produced by a forging process.We monitor the inside diameter of the rings manufactured by this process using an and an s control chart.Samples of size 4 are taken at regular intervals,and the sample means and standard deviations are computed and plotted on the charts in time order.The overall mean of the sample means is 73.812 millimeters,and the mean of the sample standard deviations is 0.022 millimeters.The control chart constants are (partially)reproduced below. What is the value of the center line of the s chart?
A)0 millimeters
B)0.020 millimeters
C)0.022 millimeters
D)0.046 millimeters

Question

Piston rings for an automotive engine are produced by a forging process.We monitor the inside diameter of the rings manufactured by this process using an  and an s control chart.Samples of size 4 are taken at regular intervals,and the sample means and standard deviations are computed and plotted on the charts in time order.The overall mean of the sample means is 73.812 millimeters,and the mean of the sample standard deviations is 0.022 millimeters.The control chart constants are (partially)reproduced below.  What is the value of the center line of the s chart?
A)0 millimeters 
B)0.020 millimeters 
C)0.022 millimeters 
D)0.046 millimeters

Quizplus · Accepted Answer

The center line of an s chart is the average of the sample standard deviations. In this case, the mean of the sample standard deviations is given as 0.022 millimeters, which is the value of the center line of the s chart.

Piston Rings for an Automotive Engine Are Produced by a Forging