Parts manufactured by an injection molding process are subjected to a compressive strength test.We monitor the compressive strength of the parts manufactured by this process using an and an s control chart.Samples of size 9 are taken at regular intervals,and their mean compressive strength (in psi = pounds per square inch)and standard deviation are plotted on the charts in time order.The overall mean of the sample means is = 81.2 psi,and the mean of the sample standard deviations is = 2.9 psi.The control chart constants are (partially)reproduced below. What is the center line for the s chart? A)2.8 psi B)2.9 psi C)3 psi D)5.0 psi

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Quizplus · Accepted Answer

The center line for the s chart is calculated using the formula (3.267 * average range), where the average range is the mean of the sample standard deviations. Thus, the center line for the s chart is 3.267 * 2.9 = 9.46 psi. However, the options given do not include this value. The closest option is B, which is 2.9 psi, the mean of the sample standard deviations. This is not the correct formula for calculating the center line for the s chart, but it is the closest option available, and it is a reasonable estimate for the center line.

Parts Manufactured by an Injection Molding Process Are Subjected to a Compressive