Quantile regression with b-splines using R

Quantile_Regresion_with_B_Splines.R

require(splines)
require(quantreg)

### Create some data

x <- rnorm(100, mean=50, sd=10)
noise <- rnorm(100, sd=5)
y <- x + noise


### Basic scatterplot of data

plot(x,y)


### The SGP function creates knots at the 0.2, 0.4, 0.6, and 0.8 quantile of the provided data and the
### boundaries by extending the range by 5 percent

rq.1 <- rq(y ~ bs(x, knots=quantile(x, prob=c(0.2, 0.4, 0.6, 0.8)), Boundary.knots=extendrange(x, f=0.05)))


### Summary of results

summary(rq.1)