library(xlsx) d=read.xlsx("IMR_GDP.xlsx",header=T, sheetIndex=1) plot( d$GDP, d$IMR, xlab="GDP", ylab="IMR") plot( log(d$GDP), (d$IMR), xlab="log(GDP)", ylab="log(IMR)") plot( log(d$GDP), log(d$IMR), xlab="log(GDP)", ylab="log(IMR)") fit=loess(log(d$IMR)~log(d$GDP), span=0.8, degree=2) summary(fit) j=order(log(d$GDP)) lines(log(d$GDP)[j],fit$fitted[j], col="blue", lwd=3) d$GDP2=(log(d$GDP))^2 plot( log(d$GDP), log(d$IMR), xlab="log(GDP)", ylab="log(IMR)") fit.qua=lm(log(d$IMR)~log(d$GDP)+d$GDP2) j=order(log(d$GDP)) lines(log(d$GDP)[j],fit.qua$fitted[j], col="blue", lwd=3) fit.lin=lm(log(d$IMR)~log(d$GDP)) lines(log(d$GDP)[j],fit.lin$fitted[j], col="black", lwd=3) d$GDP3=(log(d$GDP))^3 fit.cub=lm(log(d$IMR)~d$GDP3) j=order(log(d$GDP)) lines(log(d$GDP)[j],fit.cub$fitted[j], col="orange", lwd=3)