# Formula Review

### Introduction

XN(μ, σ)

μ = the mean; σ = the standard deviation

### 6.1The Standard Normal Distribution

Z ~ N(0, 1)

z = a standardized value (z-score)

mean = 0; standard deviation = 1

To find the kth percentile of X when the z-scores is known:
k = μ + (z)σ

z-score: z = or z = $|x–μ| σ |x–μ| σ$

Z = the random variable for z-scores

Z ~ N(0, 1)

### 6.3Estimating the Binomial with the Normal Distribution

Normal Distribution: X ~ N(µ, σ) where µ is the mean and σ is the standard deviation.

Standard Normal Distribution: Z ~ N(0, 1).