MA35-01 Maths Coming soon
The complement rule: P(not A) = 1 - P(A)
This lesson is coming soon.
In this lesson
Find a missing probability from an exhaustive set of outcomes using P(not A) = 1 - P(A), and when critiquing a flawed probability diagram, name the specific incorrect values rather than stating the rule in the abstract.
What it covers
- P(A') = 1 - P(A) for a two-outcome complement
- Using 'a complete/exhaustive set of outcomes sums to 1' to find one missing probability from several known ones
- Critiquing a flawed probability diagram by citing the specific numeric values involved, not a vague 'doesn't add up' statement
Key words
For: AQA GCSE 8300, Edexcel GCSE 1MA1, Eduqas GCSE C300, Edexcel IGCSE 4MA1, OCR GCSE J560, Cambridge IGCSE 0580
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8300 | P4 | Apply the property that the probabilities of an exhaustive set of outcomes sum to 1 |
| Edexcel GCSE 1MA1 | P4 | Apply the property that the probabilities of an exhaustive set of outcomes sum to one; apply the property that the probabilities of an exhaustive set of mutually exclusive events sum to one |
| Eduqas GCSE C300 | FP4 | Apply the property that the probabilities of an exhaustive set of outcomes sum to one; apply the property that the probabilities of an exhaustive set of mutually exclusive events sum to one |
| Eduqas GCSE C300 | HP4 | Apply the property that the probabilities of an exhaustive set of outcomes sum to one; apply the property that the probabilities of an exhaustive set of mutually exclusive events sum to one |
| Edexcel IGCSE 4MA1 | F6.3H | Calculate the probability of the complement of an event happening |
| OCR GCSE J560 | 11.02e | Use the addition law for mutually exclusive events. Use p(A) + p(not A) = 1 |
| Cambridge IGCSE 0580 | C8.1 | Understand and use the probability scale from 0 to 1. |
| Cambridge IGCSE 0580 | E8.1 | Understand and use the probability scale from 0 to 1. |
For teachers
This GCSE Maths lesson teaches the complement rule: P(not A) = 1 - P(A). By the end, students should be able to find a missing probability from an exhaustive set of outcomes using P(not A) = 1 - P(A), and when critiquing a flawed probability diagram, name the specific incorrect values rather than stating the rule in the abstract. It works through two worked examples and the mistakes examiners report.