| Quality of the course | Standard | Pearson’s | ||||
| deviation | A | 2 | 3 | 4 | 5 | |
| A: Abstention | 0.84 | 1.00 | 0.36 | 0.40 | 0.34 | −0.47 |
| 2: Low quality | 0.49 | 0.36 | 1.00 | 0.65 | 0.51 | −0.64 |
| 3: Certain quality | 3.05 | 0.40 | 0.65 | 1.00 | 0.50 | −0.72 |
| 4: Quality | 8.75 | 0.34 | 0.51 | 0.50 | 1.00 | −0.96 |
| 5: High quality | 11.29 | −0.47 | −0.64 | −0.72 | −0.96 | 1.0 |
| Spearman’s | ||||||
| A: Abstention | 0.84 | 1.00 | 0.43 | 0.50 | 0.11 | −0.25 |
| 2: Low quality | 0.49 | 0.43 | 1.00 | 0.68 | 0.47 | −0.59 |
| 3: Certain quality | 3.05 | 0.50 | 0.68 | 1.00 | 0.52 | −0.73 |
| 4: Quality | 8.75 | 0.11 | 0.47 | 0.52 | 1.00 | −0.94 |
| 5: High quality | 11.29 | −0.25 | −0.59 | −0.73 | −0.94 | 1.0 |
| Spearman’s | ||||||
| A: Abstention | 0.84 | 1.00 | −0.28 | 0.06 | −0.34 | −0.38 |
| 2: Low quality | 0.49 | −0.28 | 1.00 | 0.35 | 0.02 | −0.63 |
| 3: Certain quality | 3.05 | 0.06 | 0.35 | 1.00 | 0.31 | −0.52 |
| 4: Quality | 8.75 | −0.34 | 0.02 | 0.31 | 1.00 | −0.84 |
| 5: High quality | 11.29 | −0.38 | −0.63 | −0.52 | −0.84 | 1.0 |
| Spearman’s | ||||||