按照quantile regression R包的说明R代码：xx<-x-mean(x);
fit1<-summary(rq(y~xx,tau=2:98/100))
fit2<-summary(rq(y~xx,tau=c(0.05,0.25,0.5,0.75,0.95)))
postscript("engelcoef.ps",horizontal=FALSE,width=6.5,height=3.5)
plot(fit1,nrow=1,ncol=2)
dev.off()
latex(fit2.caption="Engel`sLaw",transpose-TRUE)




怎么画不出下面图形