3.5.3.1.8 Forecast


Description

Minimum Origin Version Required: 2019 SR0

This function performs linear regression on a group of XY data to calculate or predict Y at the given X value. The Y value is predicted as  a + bx :

where,

b = \frac{\sum{(x-\bar{x})(y-\bar{y})}}{\sum{(x-\bar{x})^2}}

a = \bar{y} - b \bar{x}

\bar{x} and \bar{y} are the means of x and y.


Syntax

double Forecast( double x, vector vx, vector vy)


Parameters

x

The x coordinate(s) for calculating y coordinate(s).

vx

The source x coordinates used for linear regression.

vy

The source y coordinates used for linear regression.


Return

Return the calculated or predicted y coordinate at specified x coordinate.

Example

newbook;
worksheet -a 2;
col(a)={0:0.5:10};
col(b)=10*col(a)-20*rnd();
col(c)={20:1:25};
col(d)=forecast(col(c),col(a),col(b));

See Also

Slope, Intercept