| Scale | The number of observation variable | Cronbach’s Alpha | ||
| Before testing | After testing | Observation variable was removed | ||
| 1. TC | 4 | 3 | 1 | 0.930 |
| 2. DK | 5 | 5 | None | 0.916 |
| 3.TL | 7 | 7 | None | 0.943 |
| 4. DT | 4 | 4 | None | 0.906 |
| 5. CT | 5 | 5 | None | 0.923 |
| 6. DN | 4 | 4 | None | 0.904 |
| Total | 29 | 28 | 1 |
|