A GAM is a GLM in which the linear predictor is given by a user-specified sum of smooth functions of the covariates plus a conventional parametric component of the linear predictor. Assume that a sample of n objects has a response variable y and r explanatory variables x1,. . . , xr. In these assumptions, the regression equation becomes:
Here, the functions f1, f2,…., fr are different nonlinear functions on variables x. Into the GAM, the linear relationship between the response and predictors are replaced by several nonlinear smooth functions to model and capture the nonlinearities in the data.
We can see the GAM ...