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 value would we use for the center line of the chart? A)68.003 millimeters B)73.790 millimeters C)73.812 millimeters D)154.119 millimeters

Question

Quizplus · Accepted Answer

The center line of an s control chart is calculated by taking the average of the sample standard deviations. The mean of the sample standard deviations is given in the problem as 0.022 millimeters, so we would use this value as the center line. Therefore, the answer is C)73.812 millimeters.

Piston Rings for an Automotive Engine Are Produced by a Forging