Dundas Chart for Windows Forms
FTest Method
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DundasWinChart Assembly > Dundas.Charting.WinControl Namespace > Statistics Class : FTest Method


probability
The alpha value (probability that the hypothesis is rejected). Allowable range is 0-1.
Probability
firstInputSeriesName
The name of the series that stores the first group of data. Data must be stored in the first Y-values of the series' data points.
First Input Series Name
secondInputSeriesName
The name of the series  that stores the second group of data. Data must be stored in the first Y-values of the series' data points.
Second Input Series Name

Enterprise Edition Only Feature. This method performs an F Test using F distribution, and is used to see if two samples have different variances.


This analysis tool performs a two-sample F-test to compare two population variances. For example, you can use an F-test to determine whether the time scores in a swimming meet have a difference in variance for samples from two teams.

Syntax

Visual Basic (Declaration)  
Public Function FTest( _
   ByVal probability As Double, _
   ByVal firstInputSeriesName As String, _
   ByVal secondInputSeriesName As String _
) As FTestResult
Visual Basic (Usage) Copy Code
Dim instance As Statistics
Dim probability As Double
Dim firstInputSeriesName As String
Dim secondInputSeriesName As String
Dim value As FTestResult
 
value = instance.FTest(probability, firstInputSeriesName, secondInputSeriesName)

Parameters

probability
The alpha value (probability that the hypothesis is rejected). Allowable range is 0-1.
Probability
firstInputSeriesName
The name of the series that stores the first group of data. Data must be stored in the first Y-values of the series' data points.
First Input Series Name
secondInputSeriesName
The name of the series  that stores the second group of data. Data must be stored in the first Y-values of the series' data points.
Second Input Series Name

Return Value

Returns Result class from F Test

Example

The following sample performs an F Test, using Series1 and Series2 for the input series.
Visual Basic Copy Code
Imports Dundas.Charting.WinControl
...

' Perform the F test
Dim result As FTestResult = Chart1.DataManipulator.Statistics.FTest(0.05,"Series1","Series2")
C# Copy Code
using Dundas.Charting.WinControl;
...

// Perform the F test
FTestResult result = Chart1.DataManipulator.Statistics.FTest(0.05,"Series1","Series2");

Remarks

This method returns the results of the F-test using an FTestResult object.

FTest performs a two-sample F-test to compare two population variances. For example, it can be used to determine whether the time scores in a swimming meet have a difference in variance for samples from two teams.

If a specified input series does not exist in the series collection at the time of the method call than an exception will be thrown.

The following is a brief description of the FTestResult class members:

Member Description
FirstSeriesMean  The mean of the first data group.
SecondSeriesMean  The mean of the second data group.
FirstSeriesVariance  The variance of the first data group.
SecondSeriesVariance  The variance of the second data group. 
FValue  The F value.
ProbabilityFOneTail Probability F value (one tail).
FCriticalValueOneTail F critical value (one tail).

Requirements

Target Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows Server 2008 family

See Also

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