Consider a validation set that contains 500 positive examples and 500 negative examples. For R1, suppose the number of positive examples covered by the rule is 200, and the number of negative examples covered by the rule is 50. For R2, suppose the number of positive examples covered by the rule is 100 and the number of negative examples is 5. Compute vIREP for both rules. Which rule does IREP prefer?

The RIPPER algorithm (by Cohen [1]) is an extension of an earlier algorithm


called IREP (by F ?urnkranz and Widmer [3]). Both algorithms apply the


reduced-error pruning method to determine whether a rule needs to be


pruned. The reduced error pruning method uses a validation set to estimate


the generalization error of a classifier. Consider the following pair of rules:





The RIPPER algorithm (by Cohen [1]) is an extension of an earlier algorithm


called IREP (by F ?urnkranz and Widmer [3]). Both algorithms apply the


reduced-error pruning method to determine whether a rule needs to be


pruned. The reduced error pruning method uses a validation set to estimate


the generalization error of a classifier. Consider the following pair of rules:





where P is the total number of pos

For this problem, P = 500, and N = 500.

For rule R1, p = 200 and n = 50. Therefore,