Graphics Reference
In-Depth Information
Figure 6-21. A violin plot
Discussion
Violin plots are a way of comparing multiple data distributions. With ordinary density curves, it
is difficult to compare more than just a few distributions because the lines visually interfere with
each other. With a violin plot, it's easier to compare several distributions since they're placed side
by side.
A violin plot is a kernel density estimate, mirrored so that it forms a symmetrical shape. Tradi-
tionally, they also have narrow box plots overlaid, with a white dot at the median, as shown in
Figure 6-22
.
Additionally, the box plot outliers are not displayed, which we do by setting
out-
lier.colour=NA
.:
p
+
geom_violin()
+
geom_boxplot(width
=
.1
, fill
=
"black"
, outlier.colour
=
NNA
)
+
stat_summary(fun.y
=
median, geom
=
"point"
, fill
=
"white"
, shape
=
21
, size
=
2.5
)
