Private Sub CommandButton4_Click()
       Dim ws2 As Worksheet
       Dim y_out As Range
       Dim y_in As Range
       Dim x_in As Range
       Dim x_out As Range
       Dim length As Long

       Set ws2 = Sheets("Sheet2")
       For i = 1 To datasets

                length = ws2.Cells(ws2.Rows.Count, i + 4).End(xlUp).Row

                Set y_out = ws2.Range(ws2.Cells(2, 2), ws2.Cells(length, 2))
                Set y_in = ws2.Range(ws2.Cells(2, 4), ws2.Cells(length, 4))
                Set x_in = ws2.Range(ws2.Cells(2, 3), ws2.Cells(length, 3))
                Set x_out = ws2.Range(ws2.Cells(2, 1), ws2.Cells(length, 1))

                y_out.FormulaArray = "=loess(x_in;y_in;x_out;50)"

                FormulaArray = _
                "=loess(RC[1]:R[490]C[1],RC[2]:R[490]C[2],RC[-1]:R[490]C[-1],50)"

            End If
       Next i

    End Sub