NRES / STAT 803 Week 6

Generalized Additive Models

In this week we’ll look at breaking the assumption that the covariates are linearly related to the inverse link of E(Y).

Learning Objectives

  • Detect violations of the linear assumption in residual plots
  • Use a penalized smooth spline term to fit an arbitrary non-linear function
  • Decide what type of model to use based on the properties of the data


  1. Here’s a handout that I call putting it all together. I’m not sure when the best time is give you this handout, but now seems to be a good time. In the first part, which deals with deciding what sort of models to fit, when you get to step 6 just answer NO and you’ll be good. Otherwise you will probably understand what the answer yes means in a few weeks. The 2nd part is my guidelines for model selection. These are my opinion and a fair facsimile of my usual practice; they should not be taken as absolute rules supported by independent statistical theory.

  2. Optional online help session 10-11, read, watch videos, homework, discuss the handout if needed.


  1. Before Wednesday’s class


  1. Friday’s lab assignment has lots of looking at residual plots. Submit on canvas, midnight Tuesday of Week 7.

  2. Week 6 Homework is due Midnight Tuesday of Week 8.

Andrew Tyre
Professor of Wildlife Ecology
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