## ----------------------------------------------------------------------------
##   R scripts for Haerdle/Mueller/Sperlich/Werwatz: "Nonparametric and
##   Semiparametric Modelling", Springer Series in Statistics, 2004
## ----------------------------------------------------------------------------
##   Script      SPMlocpolyregression
## ----------------------------------------------------------------------------
##   Description computes the regression of food on net-income 
##               for the UK 1976 expenditure data.
## ----------------------------------------------------------------------------
##   Author      Marlene Mueller, 2008/12/19
## ----------------------------------------------------------------------------

x <- read.csv2("D:\\fes76.txt", dec=".")
x <- x[,c("NIC","FOO")]
x <- x[order(x$NIC),]

plot(x,col="cyan",pch=20,main="Engel Curve")

library(KernSmooth)
mh <- locpoly(x$NIC,x$FOO,degree=0,kernel="normal",bandwidth=20)
lines(mh)
mh1 <- locpoly(x$NIC,x$FOO,degree=1,kernel="normal",bandwidth=20)
lines(mh1,col="blue",lwd=2)

legend("topright",c("NadWat","LocLin"),col=c("black","blue"),lwd=c(1,2))