- normal distribution
- a continuous random variable (RV) where μ is the mean of the distribution and σ is the standard deviation; notation: X ~ N(μ, σ); if μ = 0 and σ = 1, the RV is called the standard normal distribution
- standard normal distribution
- a continuous random variable (RV) X ~ N(0, 1); when X follows the standard normal distribution, it is often noted as Z ~ N(0, 1)
- z-score
- the linear transformation of the form z = ; if this transformation is applied to any normal distribution X ~ N(μ, σ), the result is the standard normal distribution Z ~ N(0, 1);
If this transformation is applied to any specific value x of the RV with mean μ and standard deviation σ, the result is called the z-score of x. The z-score allows us to compare data that are normally distributed but scaled differently.