Table 4: Results for the external test set (TROUT).

Predicted
< 1 mg/L 1- 10 mg/L 10 - 100 mg/L > 100 mg/L Observed
24 62 35 19 < 1 mg/L
5 53 40 10 1- 10 mg/L
1 14 20 21 10 - 100 mg/L
2 8 14 23 > 100 mg/L