# Difference between revisions of "SigmaXX Command"

From GeoGebra Manual

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− | ; SigmaXX[ <List of | + | |

+ | ;SigmaXX[ <List of Points> ] | ||

+ | :Calculates the sum of squares of the ''x''-coordinates of the given points. | ||

+ | :{{Example|1=Let <code><nowiki>list = { (-3, 4), (-1, 4), (-2, 3), (1, 3), (2, 2), (1, 5) }</nowiki></code> be a list of points. <code><nowiki>SigmaXX[ Liste ]</nowiki></code> yields ''a = 20''.}} | ||

+ | |||

+ | |||

+ | ;SigmaXX[ <List of Raw Data> ] | ||

+ | :Calculates the sum of squares of the given numbers. | ||

:{{Example|1=In order to work out the variance of a list you may use <code>SigmaXX[list] / Length[list] - Mean[list]^2</code>.}} | :{{Example|1=In order to work out the variance of a list you may use <code>SigmaXX[list] / Length[list] - Mean[list]^2</code>.}} | ||

− | ; SigmaXX[ <List of | + | |

− | + | ||

+ | ; SigmaXX[ <List of Numbers>, <List of Frequencies> ] | ||

+ | :Calculates the weighted sum of squares of the given numbers. | ||

+ | :{{Example|1= Let <code><nowiki>list = {3, 2, 4, 3, 3, 2, 1, 1, 2, 3, 3, 4, 5, 3, 2, 1, 1, 2, 3}</nowiki></code> be a list of numbers. <code><nowiki>Unique[ list1 ]</nowiki></code> yields ''list2 = {1, 2, 3, 4, 5}'' and <code><nowiki>Frequency[ list1 ]</nowiki></code> yields ''list3 = {4, 5, 7, 2, 1}''. Command <code><nowiki>SigmaXX[ list2, list3 ]</nowiki></code> yields ''a = 144''.}} |

## Revision as of 11:33, 16 July 2013

- SigmaXX[ <List of Points> ]
- Calculates the sum of squares of the
*x*-coordinates of the given points. **Example:**Let`list = { (-3, 4), (-1, 4), (-2, 3), (1, 3), (2, 2), (1, 5) }`

be a list of points.`SigmaXX[ Liste ]`

yields*a = 20*.

- SigmaXX[ <List of Raw Data> ]
- Calculates the sum of squares of the given numbers.
**Example:**In order to work out the variance of a list you may use`SigmaXX[list] / Length[list] - Mean[list]^2`

.

- SigmaXX[ <List of Numbers>, <List of Frequencies> ]
- Calculates the weighted sum of squares of the given numbers.
**Example:**Let`list = {3, 2, 4, 3, 3, 2, 1, 1, 2, 3, 3, 4, 5, 3, 2, 1, 1, 2, 3}`

be a list of numbers.`Unique[ list1 ]`

yields*list2 = {1, 2, 3, 4, 5}*and`Frequency[ list1 ]`

yields*list3 = {4, 5, 7, 2, 1}*. Command`SigmaXX[ list2, list3 ]`

yields*a = 144*.