One-Way Anova in Visual Basic QuickStart Sample

Illustrates how to use the OneWayAnovaModel class to perform a one-way analysis of variance in Visual Basic.

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Option Infer On

Imports Numerics.NET.DataAnalysis
Imports Numerics.NET.Statistics

' Illustrates the use of the OneWayAnovaModel class for performing 
' a one-way analysis of variance.
Module AnovaOneWay

    Sub Main()
        ' The license is verified at runtime. We're using
        ' a 30 day trial key here. For more information, see
        '     https://numerics.net/trial-key
        Numerics.NET.License.Verify("64542-18980-57619-62268")

        ' This example investigates the effect of the color of packages
        ' on the sales of the product. The data comes from 12 stores.
        ' Packages can be either red, green or blue.

        ' Set up the data as anonymous records
        Dim data = {
                New With {.Store = 1, .Color = "Blue", .Shape = "Square", .Sales = 6},
                New With {.Store = 2, .Color = "Blue", .Shape = "Square", .Sales = 14},
                New With {.Store = 3, .Color = "Blue", .Shape = "Rectangle", .Sales = 19},
                New With {.Store = 4, .Color = "Blue", .Shape = "Rectangle", .Sales = 17},
                New With {.Store = 5, .Color = "Red", .Shape = "Square", .Sales = 18},
                New With {.Store = 6, .Color = "Red", .Shape = "Square", .Sales = 11},
                New With {.Store = 7, .Color = "Red", .Shape = "Rectangle", .Sales = 20},
                New With {.Store = 8, .Color = "Red", .Shape = "Rectangle", .Sales = 23},
                New With {.Store = 9, .Color = "Green", .Shape = "Square", .Sales = 7},
                New With {.Store = 10, .Color = "Green", .Shape = "Square", .Sales = 11},
                New With {.Store = 11, .Color = "Green", .Shape = "Rectangle", .Sales = 18},
                New With {.Store = 12, .Color = "Green", .Shape = "Rectangle", .Sales = 10}}
        Dim frame = DataFrame.FromObjects(data)

        ' Construct the OneWayAnovaModel object.
        Dim anova As New OneWayAnovaModel(frame, "Sales", "Color")
        ' Alternatively, you can use a formula to specify the variables
        anova = New OneWayAnovaModel(frame, "Sales ~ Color")

        ' Perform the calculation.
        anova.Fit()

        ' Verify that the design is balanced:
        If (Not anova.IsBalanced) Then
            Console.WriteLine("The design is not balanced.")
        End If

        ' The AnovaTable property gives us a classic anova table.
        ' We can write the table directly to the console:
        Console.WriteLine(anova.AnovaTable.ToString())
        Console.WriteLine()

        ' A Cell object represents the data in a cell of the model,
        ' i.e. the data related to one level of the factor.
        ' We can use it to access the group means of our color groups.

        ' First we get the IIndex object so we can easily iterate
        ' through the levels:
        Dim colorFactor = anova.GetFactor(Of String)(0)
        For Each level As String In colorFactor
            Console.WriteLine("Mean for group '{0}': {1:F4}",
                    level, anova.Cells.Get(level).Mean)
        Next

        ' We could have accessed the cells directly as well:
        Console.WriteLine("Variance for blue packages: {0}",
                anova.Cells.GetValue("Blue").Variance)
        Console.WriteLine()

        ' We can get the summary data for the entire model
        ' by using the TotalCell property:
        Dim totalSummary As Cell = anova.TotalCell
        Console.WriteLine("Summary data:")
        Console.WriteLine($"# observations: {totalSummary.Count}")
        Console.WriteLine($"Grand mean:     {totalSummary.Mean:F4}")

        Console.WriteLine("Press Enter key to continue.")
        Console.ReadLine()
    End Sub

End Module