A Simple Example of De-trending Time Series Data
Post date: May 2, 2017 7:54:57 PM
year <- 1955:2015
yield <- 100 + 0.1*year +rnorm(length(year),0,2)
yhat <- predict(lm(yield~year))
yd1 <- yield[1] - (yhat-yield) # approach 1
yd2 <- yield + coef(lm(yield~year))[2]*(year[1]-year) # approach 2
# plotting
plot(year,yield,type="o",ylim=c(290,305))
lines(year,yhat,col="red")
lines(year,yd1,type="o",col="blue")
lines(year,yd2,type="o",col="green")
cor(yd1,yd2)
# end of code