Splines and Smoothing2026-11-11splinessmoothing‑splinesnatural‑splinesbasis‑functionspolynomial‑regressionstep‑functionspenalised‑regressioneffective‑degrees‑of‑freedomnon‑parametricregressionstatisticsmath5806agenticLetting a regression function bend while keeping the fit linear in the data: polynomials, step functions, regression and natural splines, penalised splines and smoothing splines.