StatSdRuler: Compute a panel's standard deviation ruler

In coursekata: Packages and Functions for 'CourseKata' Courses

Compute a panel's standard deviation ruler

Description

StatSdRuler reduces each panel to the segment for one standard deviation, anchored at the outcome's mean. With x and y aesthetics, the outcome is y; the ruler is vertical and where places it along x. With x alone, the outcome is x and the ruler runs along the baseline from the mean to one standard deviation above it.

Usage

StatSdRuler

stat_sd_ruler(
  mapping = NULL,
  data = NULL,
  geom = "segment",
  position = "identity",
  ...,
  where = "middle",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping	Set of aesthetic mappings created by ggplot2::aes().
data	The data to be displayed in this layer.
geom	The geometric object used to display the data. Defaults to "segment".
position	A position adjustment. Defaults to "identity".
...	Other arguments passed to ggplot2::layer().
where	With both x and y mapped, where to place the ruler along x: "middle", "mean", or "median". Ignored when only x is mapped.
na.rm	If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.
show.legend	Logical. Should this layer be included in the legends?
inherit.aes	If FALSE, override the default aesthetics rather than combining with them.

Format

A ggplot2::Stat object.

Details

stat_sd_ruler() is the conventional layer constructor. It uses the same stat as gf_sd_ruler(), so both interfaces measure transformed values and compute one ruler from each panel's rows. Groups within a panel do not get separate rulers. Styling aesthetics from the source data cannot be mapped; set them to one value, or facet the plot to draw one ruler per group.

Value

stat_sd_ruler() returns a ggplot2 layer.

See Also

gf_sd_ruler() provides the ggformula interface.

Examples

ggplot2::ggplot(Fingers, ggplot2::aes(Height, Thumb)) +
  ggplot2::geom_point() +
  stat_sd_ruler(where = "mean", colour = "red", linewidth = 1)

ggplot2::ggplot(Fingers, ggplot2::aes(Thumb)) +
  ggplot2::geom_histogram(bins = 30) +
  stat_sd_ruler(colour = "red", linewidth = 1)

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