Chapter 1 Problem 1

library(ggplot2)
ggplot(mpg, aes(x=hwy, fill=drv))+
  geom_histogram(alpha=0.5)+
  theme_minimal()+
  labs(title = "Histogram", subtitle = "Histogram of Highway Miles Per Gallon", x="hwy", y="count", caption ="Source=mpg")

## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.