<P> A decision tree is a decision support tool that uses a tree - like graph or model of decisions and their possible consequences, including chance event outcomes, resource costs, and utility . It is one way to display an algorithm . </P> <P> Decision trees are commonly used in operations research, specifically in decision analysis, to help identify a strategy most likely to reach a goal, but are also a popular tool in machine learning . </P> <P> A decision tree is a flowchart - like structure in which each internal node represents a "test" on an attribute (e.g. whether a coin flip comes up heads or tails), each branch represents the outcome of the test, and each leaf node represents a class label (decision taken after computing all attributes). The paths from root to leaf represent classification rules . </P> <P> In decision analysis, a decision tree and the closely related influence diagram are used as a visual and analytical decision support tool, where the expected values (or expected utility) of competing alternatives are calculated . </P>

Which option represents the main topic of the outline