Table 2.
The 18-run split-plot I-optimal design.
| Run | X1 (%) | X2 (%) | X3 (°C)a |
|---|---|---|---|
| 1 | 13 | 0 | −10 |
| 2 | 7 | 30 | −10 |
| 3 | 10 | 15 | −10 |
| 4 | 10 | 15 | −10 |
| 5 | 10 | 15 | −10 |
| 6 | 7 | 0 | −10 |
| 7 | 13 | 30 | −10 |
| 8 | 10 | 15 | −10 |
| 9 | 10 | 30 | −20 |
| 10 | 13 | 30 | −20 |
| 11 | 7 | 15 | −20 |
| 12 | 10 | 0 | −20 |
| 13 | 10 | 0 | 0 |
| 14 | 13 | 30 | 0 |
| 15 | 7 | 15 | 0 |
| 16 | 10 | 30 | 0 |
| 17 | 13 | 15 | 0 |
| 18 | 7 | 0 | 0 |
The hard-to-change factor