# Variation & Standard Deviation

Standard deviation is a measure of how spread out the data is.

The greater the standard deviation, the greater the spread of data.

A normal distribution is usually a bell-shaped curve.

### # Characteristics of normal distribution

- Mean, mode and median are equal
- bell shaped
- Symmetrical (50% higher than mean, 50% lower)
- Most values are close to the mean
- Few individuals at extremes