Year 11 - Maths
Checking and securing calculating probabilities from diagrams
Conditional probability
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit, pupils use their knowledge of calculating theoretical probabilities and extend it to calculate conditional probabilities.
Lesson Summary
You will learn to calculate probabilities from probability trees and Venn diagrams.
Key Notes
- The probability of an outcome can be found by considering a tree diagram
- The probability of an event can be found by considering a tree diagram
- The probability of an outcome can be found by considering a Venn diagram
- The probability of an event can be found by considering a Venn diagram
Vocabulary To Learn
- Probability: The probability that an event will occur is the proportion of times the event is expected to happen in a suitably large experiment.
- Frequency: The frequency is the number of times an event occurs; or the number of individuals (people, animals etc.) with some specific property.
- Exhaustive events: A set of events are exhaustive if at least one of them has to occur whenever the experiment is carried out.
- Mutually exclusive: Two or more events are are mutually exclusive if they share no common outcome.
Common Mistakes To Avoid
- Pupils may add the probabilities along branches of a probability tree, rather than multiplying them.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The probability of an outcome can be found by considering a tree diagram. The probability of an event can be found by considering a tree diagram.
2. Use this key word in a maths sentence and explain it clearly. 'Probability'
The probability that an event will occur is the proportion of times the event is expected to happen in a suitably large experiment. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may add the probabilities along branches of a probability tree, rather than multiplying them. Correction: Remind pupils that probabilities cannot be greater than 1 and demonstrate that adding across the branches sometimes results in a probability that is greater than 1. Therefore, it must be wrong.
More Lessons In This Unit
- Advanced problem solving with conditional probability Study Guide
- Algebra in tree and Venn diagrams Study Guide
- Checking and securing calculating probabilities from tables Study Guide
- Checking and securing displaying outcomes Study Guide
- Checking and securing exhaustive events Study Guide
- Combinations Study Guide
- Comparing multiple representations to calculate conditional probabilities Study Guide
- Conditional probability in a tree diagram Study Guide
- Conditional probability in a two-way table Study Guide
- Conditional probability in a Venn diagram Study Guide
- Constructing three event Venn diagrams Study Guide
- Experimental probability Study Guide
- Experimental vs theoretical probability Study Guide
- Frequency trees Study Guide
- Probabilities in three event Venn diagrams Study Guide
- Probabilities involving algebra Study Guide
- Problem solving with conditional probability Study Guide
- Set notation Study Guide
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