The standard deviation of a set of data is a measure of the amount of variation or dispersion of the data. To calculate the standard deviation, you need to follow these steps:

- Find the mean (average) of the data set.
- Subtract the mean from each data point to find the deviation for each data point.
- Square each deviation.
- Sum all the squared deviations.
- Divide the sum of the squared deviations by the number of data points in the set.
- Take the square root of the result from step 5 to find the standard deviation.

### Here is the formula for calculating the standard deviation of a set of data:

**σ = sqrt((Σ(x_i – μ)^2) / n)**

**Where**: σ is the standard deviation x_i is each data point in the set μ is the mean of the data set n is the number of data points in the set Σ is the sum of the deviations.

Note that the standard deviation is expressed in the same units as the data.