1. The Goodman Tire and Rubber Company periodically tests its tires for tread wear under simulated road conditions. To study and control its manufacturing process, 20 samples, each containing 3 radial tires, were chosen from different shifts over several days of operation. The results are presented in the table below. Assuming that these data were collected when the manufacturing process was believed to be operating in control, develop the appropriate control charts. Discuss and make recommendations based on your charts. Tread Wear is measured in the hundredths of an inch.

Sample	Tread Wear
1	31	42	28
2	26	18	35
3	25	30	34
4	17	25	21
5	38	29	35
6	41	42	36
7	21	17	29
8	32	26	28
9	41	34	33
10	29	17	30
11	26	31	40
12	23	19	25
13	17	24	32
14	43	35	17
15	18	25	29
16	30	42	31
17	28	36	32
18	40	29	31
19	18	29	28
20	22	34	26