Modeling and Multivariate Methods - SAS

256 Performing Nonlinear Regression Chapter 9
Fit a Custom Model
Figure 9.9 Equivalence Test
decision lines
The inflection point is
outside the decision
limits, so you cannot
conclude that the
groups are equal.
The Equivalence red triangle menu has the following options:
Set Alpha Level Sets the alpha level for the test. The default value is 0.05.
Set Decision Lines Changes the decision limits for the ratio. The default values are set at 0.8 and 1.25,
representing a 25% difference.
Show Summary Report Shows or hides a report containing the parameter estimates, the decision limits,
and whether the parameter exceeded the limits.
Display Options Contains options for showing or hiding decision limits, shading, and the center line.
Also contains options for changing the appearance of the points. For additional formatting options,
right-click the graph and select Customize.
Fit a Custom Model
If you want to fit a model that is not in Fit Curve, you must first create a model column with initial
parameter estimates. This method does require a few more steps than fitting a built-in model, but it does
allow any nonlinear model to be fit. Also, you can provide a custom loss function, and specify several other
options for the fitting process.
1. Open your data table.
2. Create the model column. This column contains the formula of the model with parameters, and initial
estimates of the parameters. For details about creating a formula with parameters, see “Create a Model
Column” on page 257.
3. Select Analyze > Modeling > Nonlinear.
4. Assign the Y variable to the Y, Response role.
5. Assign the model column to the X, Predictor role.
6. Assign other roles as needed.