As of Version 7.0, IncludeConstant has been renamed to IncludeConstantBasis and is part of the built-in Wolfram Language kernel.
- To use IncludeConstant, you first need to load the Linear Regression Package using Needs["LinearRegression`"].
- The default setting IncludeConstant->True adds a constant term to the set of basis functions if a constant is not already included.
- The setting IncludeConstant->False leaves the set of basis functions unchanged.
- In the output of DesignMatrix, the constant term is included as the first column.