Question: (20 points) Twenty subgroups of size 4 are obtained for the purpose of determining trial control limits for an -and an -chart. The data are as follows

Sample#		S	Sample#		S
1	32.6	1.6733	11	29.8	1.7889
2	33.4	2.6077	12	34.0	1.7321
3	35.0	1.5811	13	33.0	3.8079
4	32.2	1.6432	14	34.8	1.7889
5	33.8	0.8367	15	35.6	2.6077
6	35.4	1.1402	16	32.8	2.4900
7	31.6	1.5166	17	33.0	2.0000
8	36.8	4.3818	18	31.6	1.5166
9	35.0	5.4314	19	28.2	3.4205
10	34.0	2.5495	20	33.8	2.3875

a) Determine the trial control limits for each chart

b) Use Minitab to verify your solution in part a)