Decision Trees

Decision Trees Q&A

1What is a decision tree?
Answer: Rule-based model splitting data recursively by feature thresholds.
2Why are trees interpretable?
Answer: Predictions follow transparent if-then paths.
3Split criteria for classification?
Answer: Gini impurity or entropy/information gain.
4Split criteria for regression?
Answer: Variance reduction or MSE reduction.
5What is overfitting in trees?
Answer: Deep trees memorize noise and generalize poorly.
6How control complexity?
Answer: Limit max depth, min samples split/leaf, and prune.
7What is pruning?
Answer: Removing weak branches to improve generalization.
8Can trees handle nonlinear relationships?
Answer: Yes, naturally through hierarchical splits.
9Do trees need feature scaling?
Answer: Usually no, unlike distance-based models.
10How handle missing values?
Answer: Some implementations support surrogate/learned split handling.
11Main limitation?
Answer: Single trees can be unstable to small data changes.
12One-line summary?
Answer: Decision trees are interpretable but often improved by ensembles.