Standard Deviations

A measure of the variability of a data set. For a simple data set with numbers, can be calculated using the following formula:

σ=(((x-xm))2/N)0.5
  • σ is standard deviation.
  • xm is the average.
  • Σ(x-xm) is the sum of xm subtracted from each individual number x.
  • N is the total number of values.

Note: Other formulas also exist.