User`s guide

Parametric Fitting
3-51
To confirm the theoretical argument that the alpha-emission data is best
described by a fourth-degree Legendre polynomial with only even terms, fit the
data using both even and odd terms:
The Linear Equations pane of the Create Custom Equation GUI is shown below
for the model given by y
2
(x).
The numerical results indicate that the odd Legendre terms do not contribute
significantly to the fit, and the even Legendre terms are essentially unchanged
from the previous fit. This confirms that the initial model choice is the best one.
y
2
x() y
1
x() a
1
xa
3
1
2
---


5x
3
3x–()++=
Create a custom linear equation
using even and odd Legendre
terms up to fourth degree.
Specify a meaningful
equation name.
Click Add a term to add the odd
Legendre terms.
The odd Legendre coefficients should not be
included in the fit because their values are
small and their confidence bounds are large.