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WalesMaths

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 on the 0 to 1 scale, use sample spaces and handle mutually exclusive and combined events?

Use the probability scale from 0 to 1, calculate probabilities of equally likely outcomes using sample spaces and listings, and apply the rules for mutually exclusive and exhaustive events including combined events in two-way tables.
A focused answer to the WJEC GCSE Mathematics probability content on the basics, covering the 0 to 1 probability scale, equally likely outcomes, sample space diagrams, mutually exclusive and exhaustive events and combined events using two-way tables and listings.
11 min answer →

How do you estimate probability from experiments using relative frequency, and predict the expected number of outcomes?

Estimate probability from experimental data using relative frequency, understand how it stabilises with more trials, compare experimental with theoretical probability, and calculate expected frequencies.
A focused answer to the WJEC GCSE Mathematics probability content on relative frequency and expected outcomes, covering estimating probability from experiments, how relative frequency stabilises with more trials, comparing experimental and theoretical probability and calculating expected frequencies.
11 min answer →

How do you use a tree diagram to find the probability of combined events, with and without replacement?

Draw and use probability tree diagrams for two or more events, multiplying along branches and adding across routes, including independent events and conditional events without replacement (Higher tier).
A focused answer to the WJEC GCSE Mathematics probability content on tree diagrams, covering drawing trees for two or more events, multiplying along branches and adding across routes, and handling conditional probability without replacement at Higher tier.
12 min answer →

How do you use Venn diagrams and set notation to organise events and calculate probabilities?

Construct and interpret Venn diagrams for two or three sets, use set notation for union, intersection and complement, and calculate probabilities from a Venn diagram (Higher tier).
A focused answer to the WJEC GCSE Mathematics probability content on Venn diagrams, covering constructing diagrams for two or three sets, the set notation for union, intersection and complement, and calculating probabilities from a Venn diagram at Higher tier.
11 min answer →