IB Math AI SL Unit 4: Statistics & Probability

IB Maths AI SL 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.

• Bivariate Data questions45 questions · 3 worked examples
• Descriptive Statistics questions36 questions · 3 worked examples
• Probability questions60 questions · 3 worked examples
• Probability Distributions questions29 questions · 3 worked examples
• Sampling Techniques questions15 questions · 3 worked examples
• Statistical Testing questions30 questions · 3 worked examples
• Two-Sample T-Test questions12 questions · 3 worked examples
• Venn Diagrams & Hard Probability questions15 questions · 3 worked examples

Learn it first: AI SL Unit 4 notes

• Conditional probability with tree diagrams
• Expected value and fair games

Where marks go in AI SL Unit 4

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

• χ² and t-tests: hypotheses, the comparison and the conclusion in context. Use a fixed layout: H₀ and H₁ in symbols with the population parameter (μ₁ = μ₂; μ₁ > μ₂) or in words naming both variables for χ²; the p-value; "p < 0.05, so reject H₀" (or not); then one sentence in context.
• Probability: adding instead of multiplying, conditional sample spaces, without replacement. Draw the tree or table. Along a branch multiply; between outcomes add. For "given that", the denominator is the size of the given group. Without replacement, the second probability changes.
• Binomial and normal: recognising the model, the bound, the tail. Binomial: fixed n, two outcomes, constant p, independent trials. Turn the words into a cumulative statement (P(X ≥ 5) = 1 − P(X ≤ 4)). For the normal, sketch and shade the region before using the GDC. An expected value can be a decimal.

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

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