IB Math AA HL Unit 4: Statistics & Probability

IB Maths AA HL Unit 4: Statistics and Probability, topic by topic

Each topic in this unit has a free page with step-by-step worked examples and the key formulas, then exam-style questions with mark schemes.

• Advanced Random Variables questions52 questions · 3 worked examples
• Conditional Probability questions33 questions · 3 worked examples

Learn it first: AA HL Unit 4 notes

• Conditional probability and Bayes' theorem
• Discrete probability distributions
• Normal distribution and standardisation
• Binomial distribution

Where marks go in AA HL Unit 4

From the IB subject reports we summarise on AA HL Examiner Insights, in our own words:

• Continuous random variables: mode, median and expectation from a pdf. Mode: x where f(x) is greatest on the domain (look at the graph and the endpoints). Median m: ∫ from the lower end to m of f(x) dx = 0.5, solved on the GDC. E(X) = ∫ x f(x) dx over the whole domain.
• Discrete probability: independence assumed, E(X²) and Var misused. E(X²) = Σ x²P(X = x): square the values, not the probabilities. Var(aX + b) = a²Var(X). Each probability must lie between 0 and 1, which gives inequalities for a parameter.

The questions here are original, written in the style of IB papers with IB-style mark schemes; for real papers see the IB Maths AA HL past papers page.

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