Table 5.
Performances of classification by CART for the two enlarged datasets. Class a), samples non-contaminated; Class b), samples below the legal limit; Class c), samples above the legal limit.
| Misclassification matrix Samples fitted assignment) | Cross-validated misclassification matrix (Samples predicted assignment) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Analytical protocol | True class | Total true samples | Assigned class | Assigned class | |||||
| a | b | c | a | b | c | ||||
| No thermal desorption pre-treatment | a | 113 | 112 | 0 | 1 | 111 | 1 | 1 | |
| Error rate: 0.0082 | rate | 0.991 | 0.000 | 0.009 | 0.982 | 0.009 | 0.009 | ||
| Risk: 0.0082 | b | 6 | 0 | 6 | 0 | 0 | 5 | 1 | |
| Cross-validated Error Rate: 0.0328 | rate | 0.000 | 1.000 | 0.000 | 0.000 | 0.833 | 0.167 | ||
| Cross-validated Risk: 0.0328 | c | 3 | 0 | 0 | 3 | 0 | 1 | 2 | |
| rate | 0.000 | 0.000 | 1.000 | 0.000 | 0.333 | 0.667 | |||
| Desorption temperature 180 °C | a | 113 | 112 | 1 | 0 | 110 | 1 | 2 | |
| Error rate: 0.0328 | rate | 0.991 | 0.009 | 0.000 | 0.973 | 0.009 | 0.018 | ||
| Risk: 0.0328 | b | 6 | 3 | 3 | 0 | 5 | 1 | 0 | |
| Cross-validated Error Rate: 0.0656 | rate | 0.500 | 0.500 | 0.000 | 0.833 | 0.167 | 0.000 | ||
| Cross-validated Risk: 0.0656 | c | 3 | 0 | 0 | 3 | 0 | 0 | 3 | |
| rate | 0.000 | 0.000 | 1.000 | 0.000 | 0.000 | 1.000 | |||