Lesson 2.03c

2.03c Calculating probabilities with diagrams Quiz: OCR Maths, Unit 13

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.03c, Calculating probabilities with diagrams: 20 multiple choice questions for the OCR Maths (H240), Unit 13: Probability, written with Revision Ninja.

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The 20 questions

  1. What set notation represents the probability of event A or event B or both occurring?

    • P(A ∩ B)
    • P(A')
    • P(A ∪ B)
    • P(A|B)

  2. Which formula correctly calculates the probability of event A given event B has occurred?

    • P(A ∩ B) / P(B)
    • P(A ∩ B) / P(A)
    • P(A) × P(B)
    • P(A ∪ B) / P(B)

  3. What is the value of P(A') if P(A) is equal to 0.35?

    • 0.65
    • 0.45
    • 0.35
    • 0.75

  4. What does the notation P(A ∩ B) represent in probability theory?

    • Either A or B
    • A given B
    • Not event A
    • Both A and B

  5. What is P(A ∪ B) if P(A) = 0.4, P(B) = 0.5, and P(A ∩ B) = 0.2?

    • 0.9
    • 0.7
    • 0.3
    • 0.8

  6. In a tree diagram, what must the probabilities on branches meeting at a single node sum to?

    • P(A)
    • 1
    • 0.5
    • 100

  7. How do you calculate the probability along a specific path in a tree diagram?

    • Multiply probabilities
    • Divide probabilities
    • Subtract probabilities
    • Add probabilities

  8. If event A and event B are mutually exclusive, what is the value of P(A ∩ B)?

    • 0.5
    • 0
    • P(A) × P(B)
    • 1

  9. Given P(A ∩ B) = 0.12 and P(B) = 0.4, what is the value of P(A|B)?

    • 0.3
    • 0.48
    • 0.52
    • 0.28

  10. Which diagram displays all possible outcomes of two independent experiments in a grid format?

    • Tree diagram
    • Sample space diagram
    • Venn diagram
    • Histograms

  11. In a Venn diagram, which region represents the complement of set A inside universal set ξ?

    • Inside circle A
    • Union region
    • Intersection region
    • Outside circle A

  12. In a two-way table, what does a grand total cell in the bottom right represent?

    • Intersection count
    • Total probability
    • Total sample size
    • Conditional outcome

  13. If events A and B are independent, which equation is always true for P(A|B)?

    • P(A|B) = 0
    • P(A|B) = P(B)
    • P(A|B) = 1
    • P(A|B) = P(A)

  14. What is P(A ∩ B) if P(A) = 0.6 and P(B|A) = 0.5?

    • 0.83
    • 0.1
    • 0.3
    • 1.1

  15. On a Venn diagram with 100 people, 40 like tea, 30 like coffee, 10 like both. How many like neither?

    • 30
    • 50
    • 20
    • 40

  16. Out of 50 students, 20 study Maths, 15 study Physics, 5 study both. What is P(Maths | Physics)?

    • 1/3
    • 1/4
    • 5/20
    • 2/5

  17. In a two-way table of 80 students, 20 are male swimmers. If 40 are swimmers, what is P(Male | Swimmer)?

    • 0.25
    • 0.5
    • 0.2
    • 0.4

  18. A bag has 3 red and 2 blue balls. Two are drawn without replacement. What is P(Second red | First red)?

    • 3/4
    • 3/5
    • 2/4
    • 2/5

  19. What is the general multiplication rule formula for P(A ∩ B) using conditional probability?

    • P(A) / P(B|A)
    • P(B) × P(A|B)
    • P(A) + P(B|A)
    • P(A) × P(B)

  20. If P(A ∪ B) = 0.8, P(A) = 0.5, and P(B) = 0.6, what is P(A ∩ B)?

    • 0.1
    • 0.3
    • 0.2
    • 0.4

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