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A Level Maths · Statistics · Year 12 and 13

A Level Maths Statistical Distributions revision

Statistical distributions covers the binomial distribution in Year 12 and the normal distribution in Year 13. Knowing when each model is appropriate matters as much as using the calculator functions.

  • Same content for AQA, Edexcel and OCR
  • Step-by-step mark schemes
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Start with one question on the binomial distribution. Stuck? Take a hint. No sign-in needed.

\(X \sim B(8, \frac{1}{2})\). Find \(P(X = 3)\). Give your answer to 3 significant figures.
Choose your answer · keys 1–4
What you need to know

Statistical Distributions in Year 12 and Year 13

AS content is usually taught in Year 12. The full A Level adds the Year 13 content. Sitting AS exams or mocks? See the AS Level Maths checklist.

Year 12 (AS content)

  • Discrete probability distributions
  • The binomial distribution B(n, p): conditions, probabilities and cumulative probabilities

Year 13 (full A Level only)

  • The normal distribution N(μ, σ²): properties, finding probabilities and unknown μ or σ
  • Using the normal distribution to approximate the binomial
  • Choosing a suitable distribution and judging the model

Worked examplemedium3 marks

The cumulative distribution function $F(x)$ for a discrete random variable $X$ is given by $F(1) = 0.2$, $F(2) = 0.7$, and $F(3) = 1$. Find $P(X=2)$.

Mark scheme and worked answer
3 steps

Then practise: skills to practise · open statistical distributions practice questions.

Try it: normal distribution calculator · inverse normal calculator · binomial distribution calculator (free, shows the working)

Where it's examined

Statistical Distributions on the AQA, Edexcel and OCR papers

Every board examines the same A Level Maths content, set by the Department for Education. Only the paper it appears on and the section numbering differ.

BoardSpecification referenceExamined in
AQA 7357AQA section NPaper 3
Edexcel 9MA0Edexcel topic Statistics 4Paper 3, Section A
OCR A H240OCR reference 2.04Paper 2, statistics section

Statistics questions can be set in the context of your board's large data set: large data set guides and practice (Edexcel · AQA · OCR A).

Practice questions

A Level Maths statistical distributions exam-style questions

Three examples from the question bank, one with its full mark scheme open. Every question comes with a step-by-step mark scheme (M, A and B marks) once you start practising.

Question 1easy2 marks

The discrete random variable $X$ has a probability distribution given by $P(X=1)=0.1$, $P(X=2)=0.3$, $P(X=3)=k$, and $P(X=4)=0.2$. Find the value of $k$.

Mark scheme: in the 7-day free trial.

Question 2medium3 marks

The random variable $X$ has probability function $P(X=x) = cx$ for $x = 1, 2, 3, 4$. Find the value of the constant $c$.

Full worked solution Free, no sign-in

  1. M1 for substituting the values of $x$ to form the sum: $c(1) + c(2) + c(3) + c(4) = 1$.
  2. M1 for simplifying to $10c = 1$.
  3. A1 for concluding $c = 0.1$.

Every question here has a full worked solution. See them all →

Question 3hard6 marks

The lengths of a species of fish are normally distributed with mean $\mu$ cm and standard deviation $\sigma$ cm. $10\%$ of the fish are longer than $80$ cm and $20\%$ are shorter than $60$ cm. Find the values of $\mu$ and $\sigma$.

Mark scheme: in the 7-day free trial.

Questions are original and written in the style of Edexcel 9MA0, and cover content that AQA and OCR examine too. They are not past-paper questions.

Full question sets with mark schemes: normal distribution questions (30) · normal approximation to the binomial questions (12)

Revision notes: Discrete distributions and the binomial distribution · The normal distribution

Play with it The shape of a normal distribution: drag the sliders

The points lie on the curve of a normal distribution. Change m (the mean) and s (the standard deviation) until the curve passes through every point. What does changing m do to the curve? What does changing s do?

Want more? Open the full Grapher.

In the practice engine

Skills you can practise

These skills sit in the Statistics unit of the UK A Level practice engine. Pick any mix of them, set the difficulty, and check each answer against its mark scheme.

Discrete random variables & distributionsThe binomial distributionBinomial cumulative probabilitiesThe normal distributionStandardising & z-valuesNormal approximation to the binomial

Open Statistics practice

Past papers

Past paper questions on statistical distributions

Statistical distributions can come up on these papers (from each board's paper structure). We haven't mapped individual questions yet, so open a recent paper and look for it.

BoardRecent papers that can test it
Edexcel 9MA0Paper 3: June 2025, June 2024, June 2023
AQA 7357Paper 3: June 2025, June 2024, June 2023
OCR H240Paper 2: June 2025, June 2024, June 2023

Papers are © the exam boards; each page links to the official question paper and mark scheme. All A Level Maths past papers →

Statistical Distributions: common questions

Is statistical distributions on the AQA, Edexcel and OCR A Level Maths exams?

Yes. Statistical Distributions is part of the A Level Maths content that every board examines: AQA section N, Edexcel Statistics 4, OCR 2.04. It is assessed in AQA Paper 3; Edexcel Paper 3, Section A; OCR A Paper 2, statistics section.

Is statistical distributions Year 12 or Year 13 content?

Both. The AS content, usually taught in Year 12, is: Discrete probability distributions; The binomial distribution B(n, p): conditions, probabilities and cumulative probabilities. The full A Level adds: The normal distribution N(μ, σ²): properties, finding probabilities and unknown μ or σ; Using the normal distribution to approximate the binomial; Choosing a suitable distribution and judging the model.

When can a binomial distribution be used?

When there is a fixed number of independent trials, each with two outcomes and the same probability of success. State these conditions in context when a question asks you to justify the model.

Your statistical distributions revision kit

More A Level Maths statistics topics

Stretch yourself: original probability problems at Senior level (ages 16 to 18), with hints and full solutions: Problem S34 · Problem S107 · Problem S101 · Problem S29. All 20 →

Formulas in this topic: Binomial distribution · Normal distribution. All formulas A–Z

Applying for maths at university? Taking STEP? STEP-style problems: Probability and statistics. STEP preparation →

Thinking about an EPQ? Maths EPQ ideas that use this topic: Modelling a school canteen queue · Why do opinion polls miss? · P-values and the replication crisis · all 93 ideas

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