如何使用Excel VBA获取多项式回归系数？

Question

I have two columns, say x and f(x) . I want to get the coefficients of the second degree equation after doing the polynomial regression in Excel VBA.

I'm a rookie in Excel VBA and have no clue what to do.

For example-

xy
-1 -1
0 3
1 2.5
2 5
3 4
5 2
7 5
9 4

The coefficients for the equation f(x)=a*x^2+b*x+c will be

a= -.008571
b= 0.99555
c= 1.648439. 

I got the coefficients using THIS website

Answer 1

In terms of using code for this, use LINEST , one way below

Sub Quaddy()
Dim X
X = Application.Evaluate("=linest(b1:B8,A1:A8^{1,2})")
MsgBox "Equation is y=" & Format(X(1), "0.###") & "x2+" & Format(X(2), "0.###") & "x+" & Format(X(3), "0.###")
End Sub

This is shown in the Excel chart below