Problem: Sampling four pieces of precision-cut wire (to be used in computer assembly) every hour for the past 24 hours has produced the following results:
| Hour |
X in " |
R in " |
| 1 |
3.25 |
0.71 |
| 2 |
3.1 |
1.18 |
| 3 |
3.22 |
1.43 |
| 4 |
3.39 |
1.26 |
| 5 |
3.07 |
1.17 |
| 6 |
2.86 |
0.32 |
| 7 |
3.05 |
0.53 |
| 8 |
2.65 |
1.13 |
| 9 |
3.02 |
0.71 |
| 10 |
2.85 |
1.33 |
| 11 |
2.83 |
1.17 |
| 12 |
2.97 |
0.4 |
| 13 |
3.11 |
0.85 |
| 14 |
2.83 |
1.31 |
| 15 |
3.12 |
1.06 |
| 16 |
2.84 |
0.5 |
| 17 |
2.86 |
1.43 |
| 18 |
2.74 |
1.29 |
| 19 |
3.41 |
1.61 |
| 20 |
2.89 |
1.09 |
| 21 |
2.65 |
1.08 |
| 22 |
3.28 |
0.46 |
| 23 |
2.94 |
1.58 |
| 24 |
2.64 |
0.97 |
Develop appropriate control limits and determine whether there is any cause for concern in the cutting process.