Calculate Filtered Results

I am trying to sum the results of a filter via VBA but cannot seem to get it right. I have the code to count the number of "active" rows, now to get an average I have been trying to use similar code to get the sum so I can divide the sum by the number of rows not filtered out. I get the error "Unable to get the Sum property of the WorkSheet function class" This is the code I have butchered:

Set R = ActiveSheet. Range("d1"). CurrentRegion
Set R = R.Offset(1, 0).Resize(R.Rows.Count - 1, R.Columns.Count)
For i = 1 To R.Rows.Count
If Not R.Rows(i).EntireRow.Hidden Then
intCountCancelled = WorksheetFunction.Sum("Cancelled") ' cancelled is a named range. This is the line its failing on
End If
Next i