IStatistics.TDist

Syntax

TDist(Value: Double; DegreesOfFreedom: Integer; Tails: Integer): Double;

Parameters

Value. The value for which the distribution needs to be calculated;

DegreesOfFreedom. An integer that indicates the number of degrees of freedom. Value must satisfy the following constraint: DegreesOfFreedom >= 1.

Tails. The number of returned distribution tails. Available values:

1. TDist function returns one-tailed distribution;
2. TDist function returns two-tailed distribution.

Description

The TDist method returns the percent points (probability) for the Student's t-distribution.

Comments

t-distribution is used to check hypotheses in case of a small sample. This function can be used instead of the table containing critical values of t-distribution.

Example

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

Sub UserProc;
Var
    st: Statistics;
    d0: Double;
Begin
    st := New Statistics.Create;
    d0 := st.TDist(2.96, 56, 1);
    If st.Status <> 0 Then
        Debug.WriteLine(st.Errors);
    Else
        Debug.WriteLine("One-tailed distribution: " + d0.ToString);
    End If;
End Sub UserProc;

After executing the example the following result is displayed in the console window:

Module execution started

Single-sided distribution: 0.0022517576411859035

Module execution finished

The result can be interpreted as 0.2251%.