Paper 2 · Statistics
⏱ Tested in 5 exam questions since 2024
Lesson 13 of 21
Statistics 13 z scores 5 (standardising formula)
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- Standardise a raw value with z = (x − μ)/σ before looking up pages 36/37
- Draw paired real-scale and z-scale diagrams for every standardising question
- Solve real-world normal problems: standardise → look up → apply complement/mirror
Most recent exam questions
- 2025 Paper 2 Q10(a)(i) — z-score lookup against the standard normal table
- 2025 Paper 2 Q10(a)(ii) — forward standardising — convert raw score 420 to z-score, look up tail probability
- 2024 Paper 2 Q7(a)(i) — standardise an individual observation — z = (x − μ)/σ, then look up P(Z < z)
- 2024 Paper 2 Q7(a)(ii) — inverse standardising — given a tail probability, find the corresponding raw value
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