Statistics

mean

x_bar = 1/n Σ x_i

permutation

nPk = n! / (n-k)!

n: size of the set

k: elements drawn

Normal Distribution

Z distribution is a normal distribution with a mean (μ) of 0 and a standard deviation (δ) of 1. Any normal distribution is described by its μ and δ value.

To convert a normal distribution to a Z distribution

 Z = (x - μ) / δ