# Chapter 6.1 and 6.2

### Sam Copeland

## Properties Of A Normal Curve

- he curve is bell-shaped.
- The curve is symmetrical about a vertical line through (U).
- The curve approaches the horizontal axis but never touches or crosses it.
- The inflection (transition) points between cupping upward and downward occur above (U) - (O).
- The area under the entire curve is 1.

## M & O

## Empirical Rule

## Control Charts

## Out Of Control Signals

Said to be out of control if the successive time measurements of

*x*indicate that it is no longer following the target probability distribution.Three of the most common warning signs are:

## Standard Scores

This tells us the number of standard deviations the measurement if from the mean.

A standard deviation score close to zero tells us the measurement is near the mean of the distribution.

A positive standard score tells us the measurement is above the mean.

A negative standard score tells us the measurement is below the mean.