# Spread of a data set - standard deviation & variance - Measures of Dispersion

### Spread of a data set - standard deviation & variance

###### Basic concepts:

- Center of a data set: mean, median, mode

###### Basic concepts:

- Center of a data set: mean, median, mode

When the values in a data set are tightly bunched together, the standard deviation will be small.

When the values in a data set are spread apart, the standard deviation will be relatively large.

$variance=\sigma^2$