VB Two Way Ranova Example

← All NMath Code Examples


Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Imports CenterSpace.NMath.Core

Namespace CenterSpace.NMath.Examples.VisualBasic

  A .NET example in Visual Basic showing two-way ranova.
  Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()

      This call is required by the Windows Form Designer.

      Add any initialization after the InitializeComponent() call

      Read in data from a file. The file contains data for a test for
      contamination of surgical scrub suits. One group of workers changed
      their scrub suit at lunch, while the other group wore a surgical 
      gown to lunch and did not change their scrub suits. Bacterial
      contamination level of the scrub suits was measured at 3 times
      during the workers shifts. The nonrepeated factor is the scrub suit
      group (change or not change), the repeated factor is time.
      Dim AnovaData As DataFrame = DataFrame.Load("TwoWayRanovaExample.dat", True, False, " ", True)

      Class TwoWayRanova performs a balanced two-way analysis of variance with
      repeated measures on one factor. Multiple linear regression is used to 
      compute the RANOVA values. The constructor takes a DataFrame
      containing the data, and the column indices of the repeated factor, 
      the nonrepeated factor, and the contamination level.
      Dim Anova As TwoWayRanova = New TwoWayRanova(AnovaData, 1, 2, 0)

      This example simply displays a traditional RANOVA table
      in a System.Windows.Forms.DataGrid object. The next few lines of
      code format the table contents.

      First retrieve the table to display. Class TwoWayRanovaTable is a
      subclass of DataFrame.
      Dim AnovaTable As TwoWayRanovaTable = Anova.RanovaTable

      Next, lets set the precision to three decimal places. Note that this
      does not actually change the numbers in the RANOVA table. It just
      determines how many decimal places are displayed when the table is
      converted to a string.
      Dim I As Integer
      For I = 1 To AnovaTable.Cols - 1
        CType(AnovaTable(I), DFNumericColumn).NumericFormat = "F3"

      Next convert the RANOVA table into a string. This has the effect of 
      formatting all the numbers so that they have three digits after the decimal
      point and all Double.NaN values are represented as a ".". (Some rows
      in the ANOVA table that do not have F statistic values or F statistic
      p-values associated with them. The cells that correspond to these rows
      and the F and P columns contain Double.NaN values.)
      Dim DisplayFrame As New DataFrame(AnovaTable.ToString(), True, True, ControlChars.Tab, False)

      Note that in the previous line we passed a value of false for the 
      parse parameter to the DataFrame constructor (the last parameter). 
      This gives us a DataFrame object in which all the column types
      are strings. This lets us format the data easily.

      If the p-value for the F statistic is too small, it is rounded
      to zero when we set the precision to three decimal places. It doesnt
      look good to have a p-value of 0 in our display, so lets display
      something a bit more sensible like display "< 0.001".
      Dim RowIndex, ColIndex As Integer
      If (AnovaTable.FstatisticPvalue("ScrubSuit") < 0.001) Then
        ColIndex = DisplayFrame.IndexOfColumn(TwoWayAnovaTable.PvalueColName)
        RowIndex = DisplayFrame.IndexOfKey("ScrubSuit")
        DisplayFrame(RowIndex, ColIndex) = "< 0.001"
      End If

      If (AnovaTable.FstatisticPvalue("Time") < 0.001) Then
        ColIndex = DisplayFrame.IndexOfColumn(TwoWayAnovaTable.PvalueColName)
        RowIndex = DisplayFrame.IndexOfKey("Time")
        DisplayFrame(RowIndex, ColIndex) = "< 0.001"
      End If

      If (AnovaTable.InteractionFstatisticPvalue < 0.001) Then
        ColIndex = DisplayFrame.IndexOfColumn(TwoWayAnovaTable.PvalueColName)
        RowIndex = DisplayFrame.IndexOfKey(TwoWayAnovaTable.InteractionRowKey)
        DisplayFrame(RowIndex, ColIndex) = "< 0.001"
      End If

      Finally, display the ANOVA table in the DataGrid.
      DataGrid1.DataSource = DisplayFrame.ToDataTable()

      The interaction effect indicates that the change in bacterial counts
      over time is different in the two groups (F = 24.163, p < 0.001). The
      main effect of time is also highly significant (F = 25.9, p 0.001). 
      The difference between scrub suit groups is insignificant (F = 3.86,
      p = 0.057).

    End Sub

    Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
      If disposing Then
        If Not (components Is Nothing) Then
        End If
      End If
    End Sub

    Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    NOTE: The following procedure is required by the Windows Form Designer
    It can be modified using the Windows Form Designer.  
    Do not modify it using the code editor.
    Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
    Friend WithEvents Label1 As System.Windows.Forms.Label
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
      Me.DataGrid1 = New System.Windows.Forms.DataGrid()
      Me.Label1 = New System.Windows.Forms.Label()
      CType(Me.DataGrid1, System.ComponentModel.ISupportInitialize).BeginInit()
      Me.DataGrid1.AllowSorting = False
      Me.DataGrid1.BackgroundColor = System.Drawing.Color.White
      Me.DataGrid1.CaptionVisible = False
      Me.DataGrid1.DataMember = ""
      Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
      Me.DataGrid1.Location = New System.Drawing.Point(16, 96)
      Me.DataGrid1.Name = "DataGrid1"
      Me.DataGrid1.PreferredColumnWidth = 110
      Me.DataGrid1.ReadOnly = True
      Me.DataGrid1.RowHeadersVisible = False
      Me.DataGrid1.Size = New System.Drawing.Size(664, 136)
      Me.DataGrid1.TabIndex = 0
      Me.Label1.Font = New System.Drawing.Font("Microsoft Sans Serif", 14.25!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
      Me.Label1.Location = New System.Drawing.Point(144, 24)
      Me.Label1.Name = "Label1"
      Me.Label1.Size = New System.Drawing.Size(376, 48)
      Me.Label1.TabIndex = 1
      Me.Label1.Text = "Two Way Anova With Repeated Measures On One Factor Example"
      Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
      Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
      Me.ClientSize = New System.Drawing.Size(698, 264)
      Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1, Me.DataGrid1})
      Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle
      Me.Name = "Form1"
      Me.Text = "Two Way Anova Example"
      CType(Me.DataGrid1, System.ComponentModel.ISupportInitialize).EndInit()

    End Sub

#End Region

  End Class

End Namespace

← All NMath Code Examples