# Standard Deviation Formula

1. Dec 12, 2008

### experimental

What is the formula for standard deviation?

2. Dec 12, 2008

### symbolipoint

Have you tried either (1) an elementary textbook on Statistics, or (2) WikiPedia? In fact, check into this: http://en.wikipedia.org/wiki/Standard_deviation

What seems unusual, is "standard" deviation exists and is distinct from "average absolute value of the deviations".

3. Dec 12, 2008

### HallsofIvy

Staff Emeritus
You might also want to decide whether you are interested in the standard deviation of a probality distribution or of a sample from a probability distribution. The formulas are slightly different.

4. Dec 13, 2008