MA36-05 Maths Coming soon
The formal conditional probability formula (OCR)
MA36-05
This lesson is coming soon.
In this lesson
Apply the formal conditional probability multiplication law P(A and B) = P(A given B) x P(B), triggered by recognising 'given that' in a question, and use P(A given B) = P(A) to test independence.
What it covers
- Recognising 'given that' as the verbal trigger for conditional probability
- The formula P(A and B) = P(A given B) x P(B)
- Rearranging the formula to find P(A given B) = P(A and B) / P(B)
- Using P(A given B) = P(A) as the definition of independence
Key words
For: OCR GCSE J560
On the specification
| Board | Spec | Statement |
|---|---|---|
| OCR GCSE J560 | 11.02f | Use tree diagrams and other representations to calculate the probability of independent and dependent combined events. |
For teachers
This GCSE Maths lesson teaches the formal conditional probability formula (OCR). By the end, students should be able to apply the formal conditional probability multiplication law P(A and B) = P(A given B) x P(B), triggered by recognising 'given that' in a question, and use P(A given B) = P(A) to test independence. It works through two worked examples and the mistakes examiners report.