set . seed (79) x

seed (79) Ilere for simplicity and reasonable comparison, please use span = 0.3365 for loess, bandwidth = 0.2 for NW kernel smoothing, and spar = 0.7163 for spline splines. That is, please use the following R code for prediction/estimation: predict (loess (y x , span O. 3365) , newdata x) ; ksmooth(x, y, kernelunormal", bandwidth 0.2, x. points=x)$y; predict (smooth. spline (y x, spar O. 7163), x=x)$y