## Standard Deviation

### STANDARD DEVIATION

Standard deviation is the measure of dispersion or distribution of the data. The standard deviation measures the spread of statistical data.

Low standard deviation is when the values are close to the mean. High standard deviation is when the values are far from the mean.

#### STANDARD DEVIATION FORMULA

**Sample standard deviation formula**

- s – sample standard deviation
- x – individual data point
- \bar{x} – sample mean
- n – total number of observation

**Population standard deviation formula**

- \sigma – population standard deviation
- x – individual data point
- \mu – population mean
- N – total number of observation

#### STANDARD DEVIATION CALCULATION STEPS

- Find the mean of the given data set
- Subtract the mean from each data point and square the result
- Sum all the squared difference and divide it by n-1 for the sample or divide by N for the population
- Square root the obtained value to get the standard deviation