Fixing problems with model diagnostics
You can use gam.check() to improve models by updating them based on its results.
This exercise is part of the course
Nonlinear Modeling with Generalized Additive Models (GAMs) in R
Exercise instructions
- Run the model diagnostics on
mod. - Based on the diagnostics, re-fit the model as
mod2, changing the number of basis functions (k) for failing smooths. - Run the model diagnostics on
mod2to ensure you have fixed the issue.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
library(mgcv)
# Fit the model
mod <- gam(y ~ s(x0, k = 3) + s(x1, k = 3) + s(x2, k = 3) + s(x3, k = 3),
data = dat, method = "REML")
# Check the diagnostics
___
# Refit to fix issues
mod2 <- gam(y ~ s(x0, k = ___) + s(x1, k = ___) + s(x2, k = ___) + s(x3, k = ___),
data = dat, method = "REML")
# Check the new model
___