In class Exercise 3 Quantile regression

library(Brq)

data(USgirl, package="Brq")

plot(USgirl, pch='.', bty="n",
     xlim=c(0, 25),
     ylim=c(0, 150),
     xlab="Age (in years)",
     ylab="Body weight (in kg)")

library(ggplot2)

#plot

ggplot(USgirl, aes(Age, Weight)) + 
 geom_point(alpha=.5, size=rel(.3)) + 
 geom_quantile(quantiles=1:5/10, 
               formula=y ~ x)+
 labs(x="Age (in years)", 
      y="Body weight (in kg)") +
 theme_minimal()