How to work with every cell in an array?

[Radka]

Jacob, I have changed my Sub, but everey time when I put "Range(...)" in my Sub, the message is appeared "Wrong number of arguments or invalid property assigment".

My new Sub is:

Sub Voltage()
    Dim Voltage
    Dim Difference
    Dim i As Integer
    Dim AvrPoints As Boolean
    AvrPoints = False
    ActiveCell.Offset(0, 1).Select
    Dim LastRow As Long
      LastRow = Range("B65536").End(xlUp).Row
Do Until AvrPoints = True
For i = 1 To LastRow
Voltage = Application.WorksheetFunction.Average(Range("B1:B" & i))
Diference = Cells(i + 1, 0) - Voltage
If Difference > 0.0004 Then
       AvrPoints = True
   End If
   Next i
Loop
    MsgBox Voltage
End Sub

But it doesn't work again.