GCSE Maths (Edexcel)
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Probability Tree Diagrams
- Probability tree diagrams break down the probabilities for a series of events
- They show the probability of specific events occurring from random actions
- Events on the diagram should be exhaustive and mutually exclusive
- The total probability of a set of branches after an event should equal one
- Constructing and reading tree diagrams is important
- Example: Sarah has a 75% chance of waking up before 8am, if she does, there's a 90% chance she'll get to work on time, if she doesn't, there's a 40% chance she'll be late
- Constructing the tree diagram involves drawing branches and writing the events they represent, and labeling them with the given probabilities
- Missing probabilities can be found by using the fact that the probabilities from a set of branches total 100%
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