# Prob. & Stat.

### 6.1 - 6.2

## Normal Curve

## μ - Sample Mean σ - Standard Deviation

## Empirical Rule

## What is the Empirical Rule?

The empirical rule states that for a normal distribution, nearly all of the data will fall within three standard deviations of the mean.

The empirical rule can be broken down into three parts:

- 68% of data falls within the first standard deviation from the mean.
- 95% fall within two standard deviations.
- 99.7% fall within three standard deviations.

## Control Chart

## Z-Score

## What exactly is a z-score?

A **z**-**score** (aka, a standard **score**) indicates how many standard deviations an element is from the mean. A **z**-**score** can be calculated from the following formula. **z** = (X - μ) / σ where **z** is the **z**-**score**, X is the value of the element, μ is the population mean, and σ is the standard deviation.

### TEST THURSDAY

### Thursday, Jan. 14th, 9-10am

### 17521 Monitor Avenue

#### Baton Rouge, LA

Know everything from formulas to small details listed above!