Q2.5 Which of the following statements are true? Select all correct statements.

Choice 1 of 4:Precision-Recall (PR) curves must be monotonically decreasing.

Choice 2 of 4:If two classifiers P-R curves intersect, at the point of intersection the two classifiers have identical confusion matrices.

Choice 3 of 4:At any precision value, the best performing classifier is the classifier with a highest recall value.

Choice 4 of 4:ROC is insensitive to the label imbalance.

Q2.1 Choose all correct ones:

Choice 1 of 4:The best threshold to flip the prediction label for binary classification is the probability of 0.5.

Choice 2 of 4:Mean of the Average Precision is useful to compare the prediction performance across multiple classes.

Choice 3 of 4:Precision-Recall curve may be more useful in practice if you the "positive" class is much more interesting but rarer than the "negative" class.

Choice 4 of 4:Even under the same ROC curve, the best classifier could be different based on the nature of the problem.