Decision Trees

Classification and Regression Trees (CART)

Motivation: Approximating Bayes Estimators

Inhomogeneity (Impurity) Measure

Categorical Predictors

Bagging

Bootstrap Samples

Random Forest

Variance Reduction in Averaging Correlated Models

Algorithm Outline

Practical Suggestions

Relative Feature Importance

Proximity Plot

Boosting

AdaBoost.M1: Algorithm Outline

Forward Stage-wise Additive Modeling

AdaBoost as a Additive Model

Exponential Loss

Robust Loss Functions

Gradient Boosting: Algorithm Outline

Relative Feature Importance