Difference between revisions of "SigmaXY Command"
From GeoGebra Manual
m |
Noel Lambert (talk | contribs) |
||
| Line 1: | Line 1: | ||
<noinclude>{{Manual Page|version=5.0}}</noinclude>{{command|statistics}} | <noinclude>{{Manual Page|version=5.0}}</noinclude>{{command|statistics}} | ||
| − | ; SigmaXY[ | + | ; SigmaXY[ <List of Points> ] |
:Calculates the sum of the products of the ''x''- and ''y''-coordinates. | :Calculates the sum of the products of the ''x''- and ''y''-coordinates. | ||
:{{Example|1=You can work out the covariance of a list of points using <code>SigmaXY[list]/Length[list] - MeanX[list] * MeanY[list]</code>.}} | :{{Example|1=You can work out the covariance of a list of points using <code>SigmaXY[list]/Length[list] - MeanX[list] * MeanY[list]</code>.}} | ||
| − | ;SigmaXY[ | + | ;SigmaXY[ <List of x-coordinates>, <List of y-coordinates> ] |
:Calculates the sum of the products of the ''x''- and ''y''-coordinates. | :Calculates the sum of the products of the ''x''- and ''y''-coordinates. | ||
:{{Example|1=Let <code><nowiki>A = (-3, 4)</nowiki></code>, <code><nowiki>B = (-1, 4)</nowiki></code>, <code><nowiki>C = (-2, 3)</nowiki></code> and <code><nowiki>D = (1, 3)</nowiki></code> be points. <code><nowiki>{x(A), x(B), x(C), x(D)}</nowiki></code> yields the x-coordinates of the points in a list ''list1 = {-3, -1, -2, 1}'' and <code><nowiki>{y(A), y(B), y(C), y(D)}</nowiki></code> yields the y-coordinates of the points in a list ''list2 = {4, 4, 3, 3}''. Command <code><nowiki>SigmaXY[ list1, list2 ]</nowiki></code> yields ''a = -19''.}} | :{{Example|1=Let <code><nowiki>A = (-3, 4)</nowiki></code>, <code><nowiki>B = (-1, 4)</nowiki></code>, <code><nowiki>C = (-2, 3)</nowiki></code> and <code><nowiki>D = (1, 3)</nowiki></code> be points. <code><nowiki>{x(A), x(B), x(C), x(D)}</nowiki></code> yields the x-coordinates of the points in a list ''list1 = {-3, -1, -2, 1}'' and <code><nowiki>{y(A), y(B), y(C), y(D)}</nowiki></code> yields the y-coordinates of the points in a list ''list2 = {4, 4, 3, 3}''. Command <code><nowiki>SigmaXY[ list1, list2 ]</nowiki></code> yields ''a = -19''.}} | ||
Revision as of 21:27, 22 August 2015
- SigmaXY[ <List of Points> ]
- Calculates the sum of the products of the x- and y-coordinates.
- Example: You can work out the covariance of a list of points using
SigmaXY[list]/Length[list] - MeanX[list] * MeanY[list].
- SigmaXY[ <List of x-coordinates>, <List of y-coordinates> ]
- Calculates the sum of the products of the x- and y-coordinates.
- Example: Let
A = (-3, 4),B = (-1, 4),C = (-2, 3)andD = (1, 3)be points.{x(A), x(B), x(C), x(D)}yields the x-coordinates of the points in a list list1 = {-3, -1, -2, 1} and{y(A), y(B), y(C), y(D)}yields the y-coordinates of the points in a list list2 = {4, 4, 3, 3}. CommandSigmaXY[ list1, list2 ]yields a = -19.
