Difference between revisions of "SigmaXY Command"
From GeoGebra Manual
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; SigmaXY( <List of Points> ) | ; 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 | + | :{{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( <List of x-coordinates>, <List of y-coordinates> ) | ;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 | + | :{{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''.}} |
Latest revision as of 09:10, 12 October 2017
- 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.