What Is a Tree Diagram?
What Is a Tree Diagram?
A tree diagram shows all the possible outcomes of an event and their probabilities.
A Real Example of a Tree Diagram
It is easier to understand a tree diagram with an example.
Tossing a Coin
If a coin is tossed, the coin can land on Heads or Tails.

Each outcome has its own branch. There is a branch for Heads and for Tails.

The probability of each outcome is written by each branch. The probability of Heads (^{1}⁄_{2}) is written by the branch. The probability of Tails (^{1}⁄_{2}) is written by the branch.
Note: The probabilities across the branches add up to 1. They are mutually exclusive and exhaustive events.
Another Real Example of a Tree Diagram
A tree diagram can be extended to more than one event.
The tree diagram below is for two coin tosses.