Standard Deviation

A standard deviation is basically a static tool to measure the dispersion of the dataset values from the mean. Mean is the average of two or more numbers in the dataset.
 

The standard deviation is calculated as the square root of the variance. Variance is the measurement of the spread between the numbers in a dataset. 

When the dataset values are further from the mean, the deviation in the dataset is higher. Hence, higher the spread in the dataset values, higher the standard deviation.

The formula of standard deviation is:

Where,