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LearnCambridge97092026–2027Paper 5 · Probability & Statistics 1Probability
Paper 5 · Module

Probability

3 subtopics≈ 100 min in total
Start the module: Combined events and Venn diagramsOpen graphing calculator

  1. Combined events and Venn diagrams

    Probability starts with counting equally likely outcomes. A sample space lists them; a Venn diagram shows how events overlap; and the addition rule stops the overlap being counted twice.

    ≈ 30 min

  2. Tree diagrams and conditional probability

    Multiply along the branches, add between branches. "Given that" shrinks the sample space to the outcomes you know have happened, and P(A∣B)=P(A∩B)P(B)P(A\mid B)=\dfrac{P(A\cap B)}{P(B)} does the shrinking.

    ≈ 40 min

  3. Independent and mutually exclusive events

    Two ideas that are easy to mix up. Mutually exclusive events cannot happen together, so their probabilities add. Independent events do not affect each other, so their probabilities multiply.

    ≈ 30 min