Standard deviation is used to measure the amount of variation of a set of values. A low standard deviation indicates that the values tend to be close to the mean of the set, while a high standard deviation indicates that the values are spread out over a wider range.

There are 2 types of equations: Sample and Population.

## Population Standard Deviation

Population Standard Deviation (σ) is used with an entire population or with sample of a large population which could be genealized to a population.

**µ**: Population average

**Xi**: Individual values

**N**: Count of values

## Sample Standard Deviation

Sample Standard Deviation (s), is used to make a statement about the population standard deviation from wich sample is drawn.

**x¯**: Sample average

**Xi**: Individual values

**N**: Count of values