"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. Decision trees are commonly
used in operations research, specifically in decision analysis, to help identify
a strategy most likely to reach a goal. Another use of decision trees is as a descriptive
means for calculating conditional probabilities.
In decision analysis, a "decision tree" — and the closely related influence
diagram — is used as a visual and analytical decision support tool, where the expected
values (or expected utility) of competing alternatives are calculated.
A decision tree consists of 3 types of nodes:
1. Decision nodes:
commonly represented by squares
2. Chance nodes:
represented by circles
3. End nodes:
represented by triangles