Year 11 - Maths
Conditional probability in a two-way table
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 a conditional probability from a two-way table.
Key Notes
- A two-way table can be used to calculate conditional probabilities
- A two-way table can be used to calculate conditional probabilities involving sets of events
- Two-way tables allow us to identify which events are mutually exclusive
- Two-way tables can be used to identify which events are independent
Vocabulary To Learn
- Conditional probability: Conditional probability is the probability of an outcome occurring given that another event has occurred.
- Mutually exclusive: Mutually exclusive events have no outcomes in common.
- Independent events: Event A is independent of event B if the probability of event A occurring is not affected by whether or not event B occurs.
Common Mistakes To Avoid
- Pupils may conflate the meaning of mutually exclusive with the meaning of independent.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
A two-way table can be used to calculate conditional probabilities. A two-way table can be used to calculate conditional probabilities involving sets of events.
2. Use this key word in a maths sentence and explain it clearly. 'Conditional probability'
Conditional probability is the probability of an outcome occurring given that another event has occurred. 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 conflate the meaning of mutually exclusive with the meaning of independent. Correction: Emphasise the word 'exclusive' in 'mutually exclusive' to suggest that one event excludes the other. Also, emphasise that the opposite of independent is dependent.
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 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 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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