show_mean: Mark a Distribution's Mean

In coursekata: Packages and Functions for 'CourseKata' Courses

Mark a Distribution's Mean

Description

Usage

show_mean(
  object = NULL,
  color = "#E60000",
  linetype = "longdash",
  linewidth = 0.7
)

Arguments

object	A plot of one distribution.
color	Line color. Default "#E60000".
linetype	Line type. Default "longdash".
linewidth	Line width. Default 0.7.

Details

Draws a vertical line at the mean of the variable a distribution is built from, spanning the count axis. Works on any plot of one distribution – gf_histogram(), gf_dotplot(), gf_squareplot(). A faceted plot gets one line per panel, at that panel's own mean, because a facet is a region with its own subset of the data. Each line spans the count axis of the panel it is drawn in, so scales = "free_y" is supported and no panel is stretched to hold another panel's line.

A plot with a variable on each axis is refused. The middle of a two-variable plot is a model, and gf_model() draws models – an hline at the mean of the outcome for the empty model. Averaging the x variable of a scatterplot would draw a line nobody asked for.

Value

The plot, with a tagged mean line added.

See Also

show_dgp() frames a sampling distribution with the process that generated it; gf_model() draws the mean of a two-variable plot's outcome.

Examples

gf_histogram(~Thumb, data = Fingers, binwidth = 5) %>% show_mean()

# a facet is a region with its own subset, so each panel gets its own mean
gf_histogram(~Thumb | Sex, data = Fingers, binwidth = 5) %>% show_mean()

coursekata documentation built on Sept. 22, 2026, 1:08 a.m.