I am having an exception when running the function PingTest() in terms of the array I'm using. I'm not entirely sure how this is happening. Here is all the code.

Code:
    Dim pingTo As String = "www.google.com"
    Dim amountOfTests As Integer = 10
    Dim testIterations(amountOfTests - 1) As Integer

    Public Function AverageOfTests() As Boolean
        Dim average As Double
        For count As Integer = 0 To amountOfTests
            average = average + testIterations(count)
            count += 1
        Next
        txtResults.Text += average

        Return True
    End Function

    Public Function PingTest() As Boolean
        For count As Integer = testIterations(count) To amountOfTests
            count += 1
            Dim ping As New System.Net.NetworkInformation.Ping
            Dim ms = ping.Send(pingTo).RoundtripTime()
            txtResults.Text += System.Environment.NewLine
            txtResults.Text += "pinged (" & pingTo & ") at " & ms & "."
            testIterations(count) = CInt(ms)

        Next
        AverageOfTests()
        Return True
    End Function

    Private Sub btnStart_Click(sender As Object, e As EventArgs) Handles btnStart.Click
        txtResults.Clear()
        PingTest()
    End Sub