Paper 2 · Statistics
⏱ Tested in 5 exam questions since 2022
Lesson 14 of 21
Statistics 14 z scores 6 (standardising sample means)
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Subscribe for full access · €199/yrIn this lesson you’ll learn to
- Standardise a sample mean with z = (x̄ − μ)/(σ/√n) instead of σ
- Spot the 'sample of n … average' wording that signals dividing by √n
- Explain why sample means cluster tighter than individuals (standard error σ/√n)
Most recent exam questions
- 2025 Paper 2 Q10(b) — two-tailed hypothesis test for a population mean using the z-statistic
- 2025 Paper 2 Q10(c)(i) — z-test statistic for a sample mean: z = (x̄ − μ₀) / (s/√n)
- 2024 Paper 2 Q7(b) — two-tailed hypothesis test for a population mean — standardise the sample mean using z =…
- 2022 Paper 2 Q5(b) — two-tailed hypothesis test for a population mean using a known sample mean, sample stand…
- 2022 Paper 2 Q7(e)(i) — distribution of sample means — x̄ ~ N(μ, (σ/√n)²)
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