generalized_boxplot: Generalized Boxplot

In ChristianGoueguel/specProc: Preprocessing Tools For Laser-Induced Breakdown Spectroscopy (LIBS) Spectra

Generalized Boxplot

Description

This function implements the generalized boxplot, a robust data visualization technique designed to effectively represent skewed and heavy-tailed distributions, as proposed by Bruffaerts et al. (2014).

Usage

generalized_boxplot(
  x,
  alpha = 0.05,
  p = 0.9,
  plot = TRUE,
  xlabels.angle = 90,
  xlabels.vjust = 1,
  xlabels.hjust = 1,
  box.width = 0.5,
  notch = FALSE,
  notchwidth = 0.5,
  staplewidth = 0.5
)

Arguments

x	A numeric data frame or tibble.
alpha	A scalar, between 0 and 1 that specifies the desired detection rate of atypical values.
p	A scalar, between 0.5 and 1 that specifies the quantile order for estimating g and h.
plot	Logical value indicating whether to plot the boxplot or return the boxplot statistics.
xlabels.angle	A numeric value specifying the angle (in degrees) for x-axis labels (default is 90).
xlabels.vjust	A numeric value specifying the vertical justification of x-axis labels (default is 1).
xlabels.hjust	A numeric value specifying the horizontal justification of x-axis labels (default is 1).
box.width	A numeric value specifying the width of the boxplot (default is 0.5).
notch	A logical value indicating whether to display a notched boxplot (default is FALSE).
notchwidth	A numeric value specifying the width of the notch relative to the body of the boxplot (default is 0.5).
staplewidth	A numeric value specifying the width of staples at the ends of the whiskers.

Details

This method extends the adjusted boxplot method by leveraging the flexible Tukey's g-and-h parametric distribution to model the underlying data structure, particularly for asymmetric or long-tailed datasets, providing a more nuanced and informative summary of the data's central tendency, spread, and potential outliers.

Value

• If plot = TRUE, returns a ggplot2 object containing the generalized boxplot.

• If plot = FALSE, returns a list of tibbles with the generalized boxplot statistics and potantial outliers.

Author(s)

Christian L. Goueguel

References

• Bruffaerts, C., Verardi, V., Vermandele, C. (2014). A generalized boxplot for skewed and heavy-tailed distributions. Statistics and Probability Letters 95(C):110–117

Examples

set.seed(123)
data <- data.frame(
  normal = rnorm(100),
  skewed = rexp(100, rate = 0.5),
  heavy_tailed = rt(100, df = 3)
)

# Plot the generalized boxplot
generalized_boxplot(data)

# Retrieve the generalized boxplot statistics
generalized_boxplot(data, plot = FALSE)

ChristianGoueguel/specProc documentation built on Nov. 9, 2024, 3:23 p.m.