#
#  Figure 8.1  Shrinkage estimators
#
par(bty="n")
par(lwd=1)
plot(8,0,xlim=c(-1,12),ylim=c(-6,6),xlab="",ylab="",xaxt="n",yaxt="n",pch=19)
segments(-1,0,12,0)
segments(0,-3.5,0,3.5)
# See plotmath for use of expression
text(-0.3,0.45,"m",vfont=c("serif symbol","bold"))
text(8.1,0.45,"q",vfont=c("serif symbol","bold"))
text(6.1,0.4,expression(bolditalic(X)[1]))
text(8.1,2.4,expression(bolditalic(X)[2]))
text(10.1,0.4,expression(bolditalic(X)[3]))
text(8.1,-1.6,expression(bolditalic(X)[4]))
c <- 5
par(lwd=2)
shrink <- function(x,y){
  points(x,y,pch=19)
  arrows(x,y,x*(1-c/(x^2+y^2)),y*(1-c/(x^2+y^2)),length=0.1)
}
shrink(6,0)
shrink(10,0)
shrink(8,2)
shrink(8,-2)
par(lwd=1)
par(bty="o")