# R code for Nonparametric Curve Smoothing


autos91 <- read.table("c:/cjdata/stat514/autos91.txt",header=T)

 

# This value for the bandwidth argument to the ksmooth function 
# creates a smoother that looks like the one in the text

plot(autos91$HP,autos91$MPG)
lines(ksmooth(autos91$HP,autos91$MPG,"normal",bandwidth=65))



# This value for the span argument to the loess.smooth function 
# creates a smoother that looks like the one in the text

plot(autos91$HP,autos91$MPG)
lines(loess.smooth(autos91$HP,autos91$MPG,span=.5))