| Design Point | Coded levels of factor | Mean fiber diameter (nm) ± Standard deviation (nm) | ||||
| X1 | X2 | X3 | X4 | Experimental | Predicted | |
| 1 | −1 | −1 | 0 | 0 | 248.3 ± 73.3 | 272.7 ± 86.4 |
| 2 | 1 | −1 | 0 | 0 | 197.6 ± 38.7 | 192.4 ± 44.2 |
| 3 | −1 | 1 | 0 | 0 | 222.6 ± 84.2 | 254.5 ± 88.6 |
| 4 | 1 | 1 | 0 | 0 | 187.1 ± 31.8 | 189.4 ± 28.6 |
| 5 | 0 | 0 | −1 | −1 | 256.4 ± 29.3 | 262.5 ± 30.4 |
| 6 | 0 | 0 | 1 | −1 | 209.2 ± 49.5 | 211.8 ± 53.0 |
| 7 | 0 | 0 | −1 | 1 | 285.3 ± 52.6 | 309.4 ± 59.0 |
| 8 | 0 | 0 | 1 | 1 | 243.2 ± 60.8 | 263.9 ± 69.6 |
| 9 (C) | 0 | 0 | 0 | 0 | 197.7 ± 37.2 | 205.2 ± 32.6 |
| 10 | −1 | 0 | 0 | −1 | 212.7 ± 34.6 | 218.2 ± 47.5 |
| 11 | 1 | 0 | 0 | −1 | 186.8 ± 39.1 | 203.7 ± 37.0 |
| 12 | −1 | 0 | 0 | 1 | 354.2 ± 115.4 | 325.9 ± 110.7 |
| 13 | 1 | 0 | 0 | 1 | 211.9 ± 38.7 | 195.0 ± 19.0 |
| 14 | 0 | −1 | −1 | 0 | 302.0 ± 79.3 | 274.7 ± 63.4 |
| 15 | 0 | 1 | −1 | 0 | 274.7 ± 35.5 | 280.2 ± 42.9 |
| 16 | 0 | −1 | 1 | 0 | 259.7 ± 80.6 | 242.8 ± 66.2 |
| 17 | 0 | 1 | 1 | 0 | 200.2 ± 64.1 | 216.0 ± 73.2 |
| 18 (C) | 0 | 0 | 0 | 0 | 213.0 ± 27.0 | 205.2 ± 32.6 |
| 19 | −1 | 0 | −1 | 0 | 327.5 ± 84.3 | 314.1 ± 73.4 |
| 20 | 1 | 0 | −1 | 0 | 278.4 ± 45.6 | 283.3 ± 57.3 |
| 21 | −1 | 0 | 1 | 0 | 328.2 ± 139.7 | 308.0 ± 124.9 |
| 22 | 1 | 0 | 1 | 0 | 195.3 ± 31.0 | 193.3 ± 38.8 |
| 23 | 0 | −1 | 0 | −1 | 191.9 ± 35.7 | 196.5 ± 35.4 |
| 24 | 0 | 1 | 0 | −1 | 218.7 ± 39.7 | 183.0 ± 24.7 |
| 25 | 0 | −1 | 0 | 1 | 222.7 ± 42.1 | 243.1 ± 54.1 |
| 26 | 0 | 1 | 0 | 1 | 255.2 ± 53.9 | 235.3 ± 51.2 |
| 27 (C) | 0 | 0 | 0 | 0 | 204.8 ± 33.5 | 205.2 ± 32.6 |