Handbook of Descriptive Statistics/Template

This a template for how an entry in the Handbook of Descriptive Statistics should look. Please copy and paste the source of this page when creating a new entry.

Description

 * Brief description of what it is and what its used for.
 * Mathematical formula
 * Link to a Wikipedia article on it.

Usages
Describe in detail here data sets and purposes on which it is most useful. Describe also data sets for which it may give misleading results.

Distributions

 * Include standard values for common distributions, if they exist. For example, a normal distribution always has a skew and kurtosis of zero.
 * Include standard error for normal distribution, and for other distributions also if possible.
 * Sampling distribution.

Calculation
Include any alternative methods of calculation, especially for large data sets, or when other measures have already been calculated.

(An example: once you have the count, sum, sum of squares, cubes and fourth powers for a data set, you can then use these to easily calculate the Mean, Std. Dev, Skew and Kurtosis, rather than having to go through the entire dataset multiple times calculating differences.)

Software
Include how it is accessed in common statistical packages, if known. Can also provide links to source code samples for calculating it, etc.