Exam-style question
Try this first
For independent events A and B with P(A) = 0.5 and P(B) = 0.5, find P(A and B).
- A.0.25
- B.3.25
- C.-2.75
- D.0.5
Model answer
What a good answer should say
- The correct answer is 0.25.
This answer is tied to the objective: M2 Understand and use conditional probability, including tree diagrams, Venn diagrams and two-way tables; understand and use the conditional probability formula P(A|B) = P(A intersection B) / P(B)..
Explanation
Why this works
Use the explanation to connect the worked answer back to M2 Understand and use conditional probability, including tree diagrams, Venn diagrams and two-way tables; understand and use the conditional probability formula P(A|B) = P(A intersection B) / P(B)..
The distractors change the result or the form of the answer. The canonical solution reaches 0.25, so 0.25 is the only option consistent with the working.
Maths method check
- Topic focus: Statistics.
- Question style: practice.
- Reasoning demand: application.
- Check the operation, notation, units, and final answer form against the question before moving on.
Common mistake
No common mistake is linked to this question yet.