(Penalised) Regression Splines
Select type of basis
Truncate power basis
Basis degrees of freedom (df):
Add a roughness penalty to B-splines?
Here a first order difference penalty is being applied.
Do you want to zoom in on the plot?
The trend is very difficult to see due to the very high positive and very low negative values of some of the basis functions. Zooming will reduce the y-axis.
Unscaled basis functions
Scaled basis functions + fitted line