SigmaXY Command
From GeoGebra Manual
Revision as of 21:27, 22 August 2015 by Noel Lambert (talk | contribs)
- 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.