# solution

The Marin Manufacturing Company (MMC) produces O-rings for high-end baby strollers. It is important for the company to maintain the high standards that so distinguish MMC from that of its competitors. The quality inspector randomly selects O-rings from the ring machine and measures the outside diameter of the ring, a critical quality dimension that determines whether the O-ring will fit properly. The dimensions (in.) from the last six samples are:

 O-ring Dimensions (in.) Sample 1 2 3 4 1 0.604 0.612 0.588 0.6 2 0.597 0.601 0.607 0.603 3 0.581 0.57 0.585 0.592 4 0.62 0.605 0.595 0.588 5 0.59 0.614 0.608 0.604 6 0.585 0.583 0.617 0.579

Assume that only these six samples are sufficient and use the data to determine control limits for an R-chart and an x-chart. You need not draw the chart here on the test, just come up with the answers to these questions:

(1) What are the Upper Control Limits and Lower Control Limits for the R chart? Show work.

(2) What are the Upper Control Limits and Lower Control Limits for the x chart? Show work.

(3) Is the process under control? Why?