By contrast, nonlinear regression analysis or nonlinear least-squares fitting (NLSF) refers to equations that are nonlinear in their parameters.

Comparing regression coefficients between models when one model is nested within another is of great practical interest when two explanations of a given phenomenon are specified as linear models. The ...

First, multiple linear regression models are considered and the design matrices are allowed to be different. Second, the predictor variables are either unconstrained or constrained to finite intervals ...