randomize richtig nutzen - aber wie?

Sub zufallszahl()
Dim i1 As Variant
Dim i2 As Variant
Dim i3 As Variant
Dim i4 As Variant
Dim i5 As Variant
Dim i6 As Variant
Dim i7 As Variant
Dim i8 As Variant
Dim i9 As Variant
Dim n As Integer
Dim a As Integer
Sheets("tabelle1").Activate
For n = 1 To 500
a:
Randomize
i1 = Rnd()
i2 = Rnd()
i3 = Rnd()
i4 = Rnd()
i5 = Rnd()
i6 = Rnd()
i7 = Rnd()
i8 = Rnd()
i9 = 1 - i1 - i2 - i3 - i4 - i5 - i6 - i7 - i8
If i9 < 0 Then GoTo a Else
Range("a" & n).Value = i1
Range("b" & n).Value = i2
Range("c" & n).Value = i3
Range("d" & n).Value = i4
Range("e" & n).Value = i5
Range("f" & n).Value = i6
Range("g" & n).Value = i7
Range("h" & n).Value = i8
Range("i" & n).Value = i9
Next n
End Sub