IStatistics.TTest

Fore Syntax

TTest(A1: Array; A2: Array; Tails: Integer; Type: Integer): Double;

Fore.NET Syntax

TTest(A1: System.Array; A2: System.Array; Tails: integer; Type: integer): double;

Parameters

A1. First data series.

A2. Second data series.

Tails. Number of distribution tails.

Type. Type of executable t-test.

Description

The TTest method returns the probability for the Student's criterion.

Comments

This function is used to determine the probability for two samples to be taken from universal sets with the same mean value.

Available Values of the Tails parameter:

1. The TTest function uses single-sided distribution.
2.The TTest function uses double-sided distribution.

Available Values of the Type parameter:

1. Paired.
2. Two-sample with equal variances (homoscedastic).
3. Two-sample with unequal variances (heteroscedastic).

For correct calculation the A1 and A2 series:

Must have equal number of points if the paired t-test is used, that is, Type = 1.
Should be non-constant.

Fore Example

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

Sub UserProc;
Var
    st: Statistics;
    d0: Double;
    x, y: 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.TTest(y, x, 2, 1);
    If st.Status <> 0 Then
        Debug.WriteLine(st.Errors);
    Else
        Debug.WriteLine("Probability: " + d0.ToString);
    End If;
End Sub UserProc;

After executing the example the console window displays the probability corresponding to the paired Student's criterion with double-sided distribution.

Fore.NET Example

The requirements and result of the Fore.NET example execution match with those in the Fore example.

Imports Prognoz.Platform.Interop.Stat;
…
Public Shared Sub Main(Params: StartParams);
Var
    st: Statistics;
    d0: Double;
    x, y: 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.TTest(y, x, 2, 1);
    If st.Status <> 0 Then
        System.Diagnostics.Debug.WriteLine(st.Errors);
    Else
        System.Diagnostics.Debug.WriteLine("Probability: " + d0.ToString());
    End If;
End Sub;