Year 9 - Maths
Using an outcome tree to display outcomes for two events
Probability: possible outcomes
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit introduces and explores the concept of liklihood as a relative measure, and demonstrates multiple ways to represent likelihood such as Venn diagrams, tree diagrams and two-way tables.
Lesson Summary
You will learn to systematically find all the possible outcomes for two events by using an outcome tree diagram.
Key Notes
- Possible outcomes for two events can be shown in an outcome tree diagram.
- The outcome tree diagram can be used to generate either an outcome table or list.
- An outcome tree can be generated from either an outcome table or list.
Vocabulary To Learn
- Tree diagrams: Tree diagrams are a representation used to model statistical/probability questions. Branches represent different possible events or outcomes.
- Outcome tree: Each branch of an outcome tree shows a possible outcome from an event or from a stage of a trial. The full outcome tree shows all possible outcomes.
- Sample space: A sample space is all the possible outcomes of a trial. A sample space diagram is a systematic way of producing a sample space.
Common Mistakes To Avoid
- Every group of branches should have the same number of branches.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Possible outcomes for two events can be shown in an outcome tree diagram. The outcome tree diagram can be used to generate either an outcome table or list.
2. Use this key word in a maths sentence and explain it clearly. 'Tree diagrams'
Tree diagrams are a representation used to model statistical/probability questions. Branches represent different possible events or outcomes. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Every group of branches should have the same number of branches. Correction: In a multi-staged trial, each stage may have a different number of outcomes. The number of branches in each group reflects the number of outcomes of a stage. This means each group of branches can be made from a different number of branches.
More Lessons In This Unit
- Comparing representations of outcomes for more than two events Study Guide
- Comparing representations of outcomes for two events Study Guide
- Equally likely outcomes Study Guide
- Experiments to determine how likely an outcome is Study Guide
- Non-equally likely outcomes Study Guide
- Problem solving with possible outcomes Study Guide
- The scale of likelihoods Study Guide
- Using a Venn diagram to display outcomes for more than two events Study Guide
- Using a Venn diagram to display outcomes for two events Study Guide
- Using an outcome tree to display outcomes for more than two events Study Guide
- Using lists to display outcomes for more than two events Study Guide
- Using lists to display outcomes for two events Study Guide
- Using two-way tables to display outcomes for two events Study Guide
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