Title: Chauvenet-type boxplot in ggplot2 — geom_chau

This function can be operated the same way as geom_boxplot() in ggplot2, except that the fence coefficient k=1.5 in Tukey's boxplot is replaced by the fence coefficient associated with Chauvenet’s criterion. For details, please refer to formula (9) in Lin et al. (2025).

Usage

geom_chau_boxplot(
  mapping = NULL,
  data = NULL,
  geom = "boxplot",
  position = "dodge2",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

Arguments

mapping: Aesthetic mappings created by `aes()`.
data: The data to be displayed in this layer.
geom: The geometric object to use for display.
position: The position adjustment.
na.rm: Logical. Should missing values be removed?
show.legend: Logical. Should this layer be included in the legends?
inherit.aes: If FALSE, overrides the default aesthetics.
...: Other arguments passed to the layer.

Value

A ggplot2 layer with the Chauvenet-type boxplot.

References

Hongmei Lin, Riquan Zhang and Tiejun Tong (2025). When Tukey meets Chauvenet: a new boxplot criterion for outlier detection. Journal of Computational and Graphical Statistics, accepted.

Examples

# Example 1
library(ggplot2)

rate.senior <- c(4.96, 6.30, -5.38, 1.60, 7.24, 5.26, 2.55, 5.96, 3.96,
                 4.19, 1.88, 4.06, 4.75, 0, 0, 2.5, 2.87, 3.00)/100
year <- 2007:2024
data.senior <- data.frame(x=year, y=rate.senior)

C.boxplot.senior <-
  ggplot(data.senior, aes(y=rate.senior)) +
  geom_chau_boxplot(fill="purple",width=3) +
  theme(legend.position = "none") +
  scale_x_discrete(breaks = NULL) +
  ylim(-0.057,0.077) +
  theme(plot.margin = unit(c(0, 0, 0, 0), "inches")) +
  labs(title="C.boxplot", subtitle="Senior civil servants", x="", y="")

print(C.boxplot.senior)