| level | Q_A | Q_B | Q_C | Q_D | ||||
| Number | percentage | Number | percentage | Number | percentage | Number | percentage | |
| low | 130 | 20 | 145 | 22.3 | 170 | 26.2 | 140 | 21.4 |
| mid | 370 | 56.9 | 360 | 55.4 | 270 | 41.5 | 330 | 50.8 |
| high | 150 | 23.1 | 125 | 19.2 | 210 | 32.3 | 180 | 27.8 |
| total | 650 | 100.0 | 650 | 100.0 | 650 | 100.0 | 650 | 100.0 |