Question: An automotive industry supplier produces pistons for several models of automobiles. Twenty samples each consisting of 200 pistons, were selected when the process was known to be operating correctly. The number of defective pistons found in the samples, follow.

? What is the estimate of the proportion defective for the piston manufacturing process in control?

? Compute a p-chart for the manufacturing

o process, assuming each sample has 200 pistons.

? With the results of part (2), what conclusion should be made if a sample of 200 has 20 defective pistons?

? Compute the upper and lower control limits for an np-chart.

? Answer part (3) using the results of part (4).