Q4) An analyst has drawn twelve samples, each containing six sample points, from a process that produces a product. The diameter of each product in the samples was determined. The results were tabulated, and sample means, and ranges were computed. The results were:

Sample
Sample	Mean (in.)	Range (in.)
1	10.012	0.009
2	10.007	0.014
3	9.991	0.007
4	10.006	0.026
5	9.997	0.016
6	9.999	0.012
7	10.001	0.008
8	10.005	0.013
9	9.995	0.015
10	10.001	0.011
11	10.003	0.014
12	10.006	0.009

a) Determine the upper and lower control limits and the overall means for x-charts and R-charts.

b) Draw the charts and plot the values of the sample means and ranges.

c) Do the data indicate a process that is in control?

d) Why or why not?