Additive Model (AM) Function

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An Additive Model (AM) Function is a model function of the form [math]\displaystyle{ Y= \beta_0+\sum_{j=1}^p f_j(X_{j})+\varepsilon }[/math].



References

2020

2020

  • (Wikipedia, 2020) ⇒ https://en.wikipedia.org/wiki/Additive_model#Description Retrieved:2020-10-2.
    • Given a data set [math]\displaystyle{ \{y_i,\, x_{i1}, \ldots, x_{ip}\}_{i=1}^n }[/math] of n statistical units, where [math]\displaystyle{ \{x_{i1}, \ldots, x_{ip}\}_{i=1}^n }[/math] represent predictors and [math]\displaystyle{ y_i }[/math] is the outcome, the additive model takes the form :

      [math]\displaystyle{ E[y_i|x_{i1}, \ldots, x_{ip}] = \beta_0+\sum_{j=1}^p f_j(x_{ij}) }[/math]

      or

      [math]\displaystyle{ Y= \beta_0+\sum_{j=1}^p f_j(X_{j})+\varepsilon }[/math] Where [math]\displaystyle{ \lt P\gt E[ \epsilon ] = 0 }[/math] , [math]\displaystyle{ Var(\epsilon) = \sigma^2 }[/math] and [math]\displaystyle{ E[ f_j(X_{j}) ] = 0 }[/math] . The functions [math]\displaystyle{ f_j(x_{ij}) }[/math] are unknown smooth functions fit from the data. Fitting the AM (i.e. the functions [math]\displaystyle{ f_j(x_{ij}) }[/math] ) can be done using the backfitting algorithm proposed by Andreas Buja, Trevor Hastie and Robert Tibshirani (1989). [2]

  1. Friedman, J.H. and Stuetzle, W. (1981). “Projection Pursuit Regression", Journal of the American Statistical Association 76:817–823.
  2. Buja, A., Hastie, T., and Tibshirani, R. (1989). “Linear Smoothers and Additive Models", The Annals of Statistics 17(2):453–555.

2015