Using smoothing parameters to avoid overfitting
The smoothing parameter balances between likelihood and wiggliness to optimize model fit. Here, you'll examine smoothing parameters and will fit models with different fixed smoothing parameters.
Este ejercicio forma parte del curso
Nonlinear Modeling with Generalized Additive Models (GAMs) in R
Instrucciones del ejercicio
- View the value of the smoothing parameter (\(\lambda\)) of the provided
gam_modmodel by extracting thespvalue from the model. - Fit two models to the
mcycledata withaccelas a smooth function oftimesand a smoothing parameter of:- 0.1
- 0.0001
- Visualize both models.
Ejercicio interactivo práctico
Prueba este ejercicio y completa el código de muestra.
library(mgcv)
# Extract the smoothing parameter
gam_mod <- gam(accel ~ s(times), data = mcycle, method = "REML")
___
# Fix the smoothing parameter at 0.1
gam_mod_s1 <- gam(accel ~ s(times), data = mcycle, sp = ___)
# Fix the smoothing parameter at 0.0001
gam_mod_s2 <- gam(___)
# Plot both models
par(mfrow = c(2, 1))
plot(gam_mod_s1, residuals = TRUE, pch = 1)
plot(gam_mod_s2, residuals = TRUE, pch = 1)