STATISTICS AND PROBABILITY

Tree Diagrams & the AND/OR rule

Tree Diagrams & the AND/OR rule

(Higher Tier)

mathsA tree diagram is a good visual representation of all possible outcomes of an event.

Each ‘branch’ of the ‘tree’ represents an outcome.

If one outcome doesn’t affect another outcome then they’re said to be independent. For example, tossing a coin or rolling a dice

Any set of branches will always add up to 1.

In order to find a probability using a tree diagram you need to multiply along the branches. For example, if you were tossing a coin and wanted to calculate the probability of three tails in a row: