True or false: In a decision tree, a variable can appear on multiple branches.

• A. False
• B. True
• C. Only In Some Trees
• D. Never

Answer: (B)

In a decision tree, splits are determined for each subset of the data at every node. Because those subsets can be quite different from one another, the same feature can be a good choice in more than one place in the tree. For example, you might split on age at the root, then on a branch you might split on income, while on another branch you could split on age again but with a different threshold. This local, subset-specific decision-making allows a variable to appear on multiple branches. So the statement is true.