• Know that if the probability of an event occurring is p, then the probability of it not occurring is 1 – p; find and record all possible mutually exclusive outcomes for single events and two successive events in a systematic way, using diagrams and tables.
  • Understand that:
    • if an experiment is repeated there may be, and usually will be, different outcomes;
    • increasing the number of times an experiment is repeated generally leads to better estimates of probability.


  • Use the vocabulary of probability in interpreting results involving uncertainty and prediction.
  • Identify all the mutually exclusive outcomes of an experiment; know that the sum of probabilities of all mutually exclusive outcomes is 1 and use this when solving problems.
  • Estimate probabilities from experimental data.
  • Compare experimental and theoretical probabilities in a range of contexts; appreciate the difference between mathematical explanation and experimental evidence.


  • Understand relative frequency as an estimate of probability and use this to compare outcomes of experiments.

Key Vocabulary:

  • certain, possible, impossible, even chance, most likely, theoretical probability, experimental probability, outcome, event, theory, sample space (diagram), simulate, mutually exclusive, tree diagram, P(n)

Suggested Lesson Outcomes:



Teaching & Learning Resources:

Probability Resources
Frequency Tables Resources
Experimental Probability Resources