IStatistics.Slope

Syntax

Slope(KnownYs: Array; KnownXs: Array): Double;

Parameters

KnownYs. Independent series.

KnownXs. Dependent series.

Description

The Slope method returns the slope of the linear regression line.

Comments

The slope is calculated by dividing the vertical distance by the horizontal distance between any two points of a straight line, i.e. the slope is the rate of change for the values along the line.

The equation of regression line slope:

For correct calculation the KnownYs and KnownXs series:

Should have equal number of points.
Should be non-constant.
Should contain more than three points.

Example

To execute the example, add a link to the Stat system assembly.

Sub UserProc;
Var
    st: Statistics;
    d0: Double;
    y, x: Array Of Double;
Begin
    y := New Double[10];
    y[00] := 1.6; y[05] := 2.1;
    y[01] := 1.7; y[06] := 2.2;
    y[02] := 1.8; y[07] := 2.3;
    y[03] := 1.9; y[08] := 2.4;
    y[04] := 2; y[09] := 2.8;
    x := New Double[10];
    x[00] := 2; x[05] := 6;
    x[01] := 4; x[06] := 15;
    x[02] := 2; x[07] := 17;
    x[03] := 5; x[08] := 14;
    x[04] := 12; x[09] := 3;
    st := New Statistics.Create;
    d0 := st.Slope(y, x);
    If st.Status <> 0 Then
        Debug.WriteLine(st.Errors);
    Else
        Debug.WriteLine("Tilt: " + d0.ToString);
    End If;
End Sub UserProc;

After executing the example the console window displays linear regression line tilt.