Repeat Exercise 8, using the S chart in place of the R chart.
In Exercise 8

The means are = 9.9892, = 0.2628, and = 0.0880.
a. Calculate the 3σ control limits for the R chart. Is the variance under control? If not, delete the samples that are out of control and recomputed and .
b. Based on the sample range , calculate the 3σ control limits for the chart. Based on the 3σ limits, is the process mean in control? If not, when is it first detected to be out of control?
c. Based on the Western Electric rules, is the process mean in control? If not, when is it first detected to be out of control?

Sample 9.99 0.28 0.09 2 10.02 0.43 0.13 10.10 0.16 0.05 9.90 0.26 0.09 9.92 0.22 0.07 10.05 0.40 0.15 9.97 0.08 0.03 9.93 0.48 0.15 10.01 0.25 0.09 9.87 0.29 0.10 9.90 0.39 0.14 9.97 0.27 0.08 10.02 0.20 0.07 9.99 0.37 0.13 .99 0.20 0.06 10.04 0.26 0.09 10.07 0.23 0.07 10.04 0.35 0.12 9.95 0.25 0.09 9.98 0.15 0.06 9.98 0.30 0.10 22 10.02 0.14 0.06 9.94 0.24 0.07 10.04 0.13 0.04 10.04 0.24 0.07 10 17 18 19 20 21 24