vb Code:
Public Class Form1
Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
If OpenFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then
'assuming each line of your text file contains a valid
'decimal, + there are no empty lines in your file
Dim numbers() As Decimal = Array.ConvertAll(IO.File.ReadAllLines(OpenFileDialog1.FileName), Function(s) CDec(s))
Dim avg As Decimal = getAvg(numbers)
Dim stdDeviation As Decimal = getStdDeviation(numbers, avg)
End If
End Sub
Private Function getAvg(ByVal d() As Decimal) As Decimal
Return d.Average
End Function
Private Function getStdDeviation(ByVal d() As Decimal, avg as decimal) As Decimal
Return Math.Sqrt(Array.ConvertAll(d, Function(n) (n - avg) ^ 2).Sum / d.length)
End Function
End Class