The and R values for 20 samples of size n = 5 are shown below. The specification limits of this product are 530-570.
(a) Construct a modified control chart with 3σ limits. Assume that if the true fraction nonconforming is as large as 1%, the process is acceptable. Is this process satisfactory?
(b) Suppose that if the true fraction nonconforming is as large as 1%, the modified control chart should detect this out-of-control condition with probability 0.9. Construct the modified chart and compare it to the chart obtained in part (a).
(c) Is this process in statistical control?