Difference between revisions of "SigmaXY Command"
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| − | <noinclude>{{Manual Page|version= | + | <noinclude>{{Manual Page|version=5.0}}</noinclude>{{command|statistics}} |
| − | {{command|statistics}} | + | ; SigmaXY( <List of Points> ) |
| − | ; SigmaXY | + | :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>.}} | ||
| − | ; SigmaXY | + | |
| − | :{{Example|1= | + | ;SigmaXY( <List of x-coordinates>, <List of 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''.}} | ||
Latest revision as of 10:10, 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.
