Standardisation
The process of converting a normal random variable X ~ N(μ, σ²) to a standard normal random variable Z ~ N(0, 1) using the transformation Z = (X - μ) / σ.
Real World
When comparing a student who scores 72% in Maths (class mean 60, σ = 8) with one who scores 68% in English (class mean 50, σ = 9), standardisation reveals the English student performed relatively better (z = 2.0 vs z = 1.5).
Exam Focus
Always show the Z = (x − μ)/σ substitution step — the method mark requires it even if you use a calculator.
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