Decision tree is a popular machine learning algorithm used for both classification and regression tasks. It is a tree-structured model that makes decisions based on the features of the input data.
The decision tree algorithm works by recursively splitting the data based on the most important features, with each split leading to a new node in the tree. The splitting process is done in a way that maximizes the information gain at each step, which is the difference between the impurity of the parent node and the sum of the impurities of the child nodes.
In a classification task, the decision tree algorithm splits the data into subsets that are as pure as possible with respect to the target variable, which is the class label. In a regression task, the decision tree algorithm splits the data into subsets that minimize the variance of the target variable.
Decision tree algorithms are easy to understand and interpret, making them a popular choice for tasks that require explainability. They are also relatively efficient in terms of computational resources and can handle both numerical and categorical data.
Some popular decision tree algorithms include the CART (Classification and Regression Trees) algorithm and the ID3 (Iterative Dichotomiser 3) algorithm. They have been used for various applications such as credit scoring, medical diagnosis, and customer segmentation.