tukeyboxplot: A Tukey box-and-whisker plot
In psyntur: Helper Tools for Teaching Statistical Data Analysis

Description Usage Arguments Value Examples

This function is a wrapper around a typical ggplot based box-and-whisker plot, i.e. using geom_boxplot, which implements the Tukey variant of the box-and-whisker plot. The y variable is the outcome variable whose distribution is represented by the box-and-whisker plot. If the x variable is missing, then a single box-and-whisker plot using all values of y is shown. If an x variable is used, this is used an the independent variable and one box-and-whisker plot is provided for each set of y values that correspond to each unique value of x. For this reason, x is usually a categorical variable. If x is a continuous numeric variable, it ideally should have relatively few unique values, so that each value of x corresponds to a sufficiently large set of y values.

tukeyboxplot(
  y,
  x,
  data,
  by = NULL,
  jitter = FALSE,
  box_width = 1/3,
  jitter_width = 1/5,
  xlab = NULL,
  ylab = NULL
)

`y`	The outcome variable
`x`	The optional independent/predictor/grouping variable
`data`	The data frame with the `y` and (optionally) `x` values.
`by`	An optional variable, usually categorical (factor or character), by which the points in the box-and-whisker plots are grouped and coloured.
`jitter`	A logical variable, defaulting to `FALSE`, that indicates if all points in each box-and-whisker plot should be shown as jittered points.
`box_width`	The width of box in each box-and-whisker plot. The default used, `box_width = 1/3`, means that boxes will be relatively narrow.
`jitter_width`	The width of the jitter relative to box width. For example, set `jitter_width = 1` if you want the jitter to be as wide the box.
`xlab`	The label of the x-axis (defaults to the `x` variable name).
`ylab`	The label of the y-axis (defaults to the `y` variable name).

A ggplot2::ggplot object, which may be modified with further ggplot2 commands.

# A single box-and-whisker plot
tukeyboxplot(y = time, data = vizverb)
# One box-and-whisker plot for each value of a categorical variable
tukeyboxplot(y = time, x = task, data = vizverb)
# Box-and-whisker plots with jitters
tukeyboxplot(y = time, x = task, data = vizverb,  jitter = TRUE)
# `tukeyboxplot` can be used with a continuous numeric variable too
tukeyboxplot(y = len, x = dose, data = ToothGrowth)
tukeyboxplot(y = len, x = dose, data = ToothGrowth,
             by = supp, jitter = TRUE, box_width = 0.5, jitter_width = 1)