Chapter 5 1번 문제

library(ggplot2)

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

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