Thanks deanop and bill

What I actually want is something which looks like this
http://phpaw.com/myscrpit/milt-up/jp...1124615026.jpg

So the task of the program is to select the number of variables then enter
their details and the SM equation. from this we would be able to calculate
the answer

I don't know if there is another way to do this. deanop, you have suggested
that i ask the user to input the coefficients, how would the form look like??



"deanop" wrote:

as promised here is the code revised to include square function

Sub coeffxi()
Dim i As Integer
Dim Prod_array(1 To 4)
Set Coeff = Range("c3:C6")
Set xi = Range("d3:d6")
Range("C8").Value = "Y ="
Range("D8").Value = Application.SumProduct(Coeff, xi)
For i = 1 To 4
Prod_array(i) = Coeff(i) * xi(i)
Next
Range("C9").Value = "SumSQ ="
Range("D9").Value = Application.SumSq(Prod_array)
End Sub

cheers,deano