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Northern IrelandMaths

Probability

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do you measure probability, use the probability scale, and handle mutually exclusive and combined events?

Use the probability scale from 0 to 1, find probabilities of single events, use that probabilities sum to 1, apply the mutually exclusive addition rule, and list outcomes with sample space diagrams.
A CCEA GCSE Mathematics answer on probability basics, covering the probability scale, single-event probability, the fact that probabilities sum to 1, mutually exclusive events and the addition rule, and listing outcomes with sample space diagrams.
10 min answer →

How do you estimate probability from experiments and predict expected outcomes?

Use relative frequency to estimate probability from experimental data, understand how estimates improve with more trials, identify bias, and calculate expected frequencies.
A CCEA GCSE Mathematics answer on relative frequency, covering estimating probability from experimental data, how estimates improve with more trials, recognising a biased experiment, and calculating expected frequencies.
10 min answer →

How do you use tree diagrams to find probabilities of combined events, with and without replacement?

Draw tree diagrams for two or more events, multiply along branches and add between branches, and handle independent events and conditional probability without replacement (Higher tier).
A CCEA GCSE Mathematics answer on tree diagrams, covering drawing trees for combined events, multiplying along branches and adding between them, independent events, and conditional probability without replacement.
11 min answer →

How do you use Venn diagrams and set notation to find probabilities of combined events?

Use Venn diagrams to organise data into sets, apply set notation for union, intersection and complement, and find probabilities from a Venn diagram (Higher tier).
A CCEA GCSE Mathematics answer on Venn diagrams and set notation, covering organising data into sets, the union intersection and complement notation, and finding probabilities from a completed Venn diagram.
10 min answer →