This is primarily used for aligning points generated through
geom_point() with dodged boxplots (e.g., a
a fill aesthetic supplied).
position_jitterdodge(jitter.width = NULL, jitter.height = 0, dodge.width = 0.75)
degree of jitter in x direction. Defaults to 40% of the resolution of the data.
degree of jitter in y direction. Defaults to 0.
the amount to dodge in the x direction. Defaults to 0.75,