In this exercise that follows, we consider a dataset mpg consisting of fuel economy data from 1999 and 2008 for 38 popular models of car.

1. Execute the bloc of code and explain the obtained result.

install.packages("ggplot2")

library(ggplot2)

bloc 1: head(mpg)

bloc 2: str(mpg)

bloc 3: summary(mpg)

bloc 4: p <- ggplot(mpg, aes(x = displ, y = hwy))

p <- p + geom_point() # add a plot layer with points

print(p)

bloc 5: p <- ggplot(mpg, aes(x = displ, y = hwy))

p <- p + geom_point(aes(colour = class))

print(p) by using R code