Exercises 3.5.5: use round()

[HossamGhorab]

In question #2: https://github.com/kangnade/ggplot2-solutions/blob/e6ef9e3b271599f6e97afc0f8a3f012f276f9385/ggplot2_solutions_chapter3.Rmd#L63 The task is a boxplot for every integer value of displ, which is a continuous variable so round() is required. Consider replacing line #63 with: geom_boxplot(aes(group = round(displ)))

Warmly, Hossam