Paper 2 · Statistics
⏱ Tested in 4 exam questions since 2017
Lesson 8 of 21
Statistics 8 – Empirical Rule
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- State the empirical rule: 68%, 95% and 99.7% of data within ±1σ, ±2σ, ±3σ
- Fill in all eight bell-curve regions BEFORE reading the question parts
- Find the percentage of normally distributed data between any whole-σ bounds
- Use the empirical rule at HL only when the question explicitly invokes it
Most recent exam questions
- 2025 Paper 2 Q10(a)(i) — empirical rule ("68–95–99.7 rule") — for a normal distribution, ~68% of values lie withi…
- 2025 Paper 2 Q2(a)(i) — empirical rule — the standard 68–95–99.7 gridlines correspond to μ − 3σ, μ − 2σ, μ − σ,…
- 2018 Paper 2 Q2(b)(iii) — the empirical rule (68–95–99.7) — fixed percentages of a normal distribution within ±1,…
- 2017 Paper 2 Q9(f) — uniform probability over a continuous range — the "wedge" of allowed fall directions ove…
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