The Standard Deviation is the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.

In other words:

1. | Average the numbers in a distribution |

2. | Subtract the number from the average |

3. | Square the differences |

4. | Average all the results |

5. | The standard deviation is the average (mean) of numbers calculated in step 4 |

**Page url:**
http://www.georgiaappraiser.com/glossary/index.html?standarddeviation.htm