FRM Part I · FRM Exam Part I · Machine-Learning Methods
Using the confusion matrix of 30 TP, 10 FP, 20 FN and 140 TN from a default classifier at a 0.5 threshold, the bank lowers the cutoff to 0.3 and the new counts are 40 TP, 30 FP, 10 FN and 120 TN. Which statement correctly describes the change?
Accuracy falls from 0.85 to 0.80, recall rises from 0.60 to 0.80, and precision falls from 0.75 to 0.571. Lowering the threshold flags more loans as defaults, catching more true defaults but also producing more false alarms.
- AAccuracy rises from 0.85 to 0.80 and the F1 score rises from 0.667 to 0.667
- BAccuracy falls from 0.85 to 0.80 and the F1 score falls from 0.667 to 0.571
- CAccuracy rises from 0.85 to 0.80 and recall falls from 0.60 to 0.57
- DAccuracy falls from 0.85 to 0.80 while recall rises from 0.60 to 0.80 and precision falls from 0.75 to 0.571Correct
Explanation
Before: accuracy = 170/200 = 0.85, recall 0.60, precision 0.75. After: accuracy = 160/200 = 0.80, recall = 40/50 = 0.80, precision = 40/70 = 0.571. Lowering the cutoff trades precision for recall. Other options misstate the direction or values.
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