What are decision trees?
A decision tree is a way to partition a dataset into distinct branches. The branches or partitions are then traversed to make simple decisions. Decision trees are produced by training algorithms, which identify how to split the data in an optimal way.
The decision process starts at the root node at the top of the tree. Each node in the tree is a decision rule. Algorithms construct these rules based on the relationship between the input data and the target labels in the training data. The values in the input data are utilized to estimate the value of the output.
Now that we understand the basic concept behind decision trees, the next concept to understand is how the trees are automatically constructed. We need algorithms that can construct the optimal tree based on the data. In order to understand it, we need to understand the concept of entropy. In this context, entropy refers to information entropy and not thermodynamic entropy. Information entropy is...