plot_qq: plot_qq

In deandevl/RregressPkg: Functions to Assist in Linear Regression

plot_qq

Description

Function plots a quantile-quantile plot (QQ-plot) for comparing an observed distribution with a normal distribution.

Usage

plot_qq(
  df = NULL,
  numeric_col = NULL,
  id_col = NULL,
  standardize = FALSE,
  title = NULL,
  subtitle = NULL,
  x_title = NULL,
  y_title = NULL,
  rot_y_tic_label = FALSE,
  x_limits = NULL,
  x_major_breaks = waiver(),
  x_minor_breaks = waiver(),
  x_labels = waiver(),
  y_limits = NULL,
  y_major_breaks = waiver(),
  y_minor_breaks = waiver(),
  y_labels = waiver(),
  axis_text_size = 11,
  pts_color = "black",
  pts_fill = "white",
  pts_shape = 21,
  pts_stroke = 1,
  pts_alpha = 1,
  pts_size = 1,
  plot_ref_line = TRUE,
  ref_line_color = "red",
  ref_line_width = 1,
  plot_ci_lines = TRUE,
  ci_lines_color = "black",
  ci_lines_width = 1,
  ci_line_type = "solid",
  labels_n = NULL,
  label_color = "red"
)

Arguments

df	A data frame with a column of numeric observations and optionally a column for observation identifications.
numeric_col	A string that names the numeric column from 'df' for QQ plotting.
id_col	An optional argument that names the column from 'df' providing each observation with a unique identification value. If this argument is NULL then row numbers of 'df' are used for identification.
standardize	A logical which if TRUE will standardize the observations under df$numeric_col.
title	A string that sets the plot title.
subtitle	A string that sets the plot subtitle.
x_title	A string that sets the observed response x axis title.
y_title	A string that sets the fitted response y axis title.
rot_y_tic_label	A logical which if TRUE rotates the y tic labels 90 degrees for enhanced readability.
x_limits	Depending on the class of df$numeric_col, a numeric/Date/POSIXct 2 element vector that sets the minimum and maximum for the x axis. Use NA to refer to the existing minimum and maximum.
x_major_breaks	Depending on the class of df$numeric_col, a numeric/Date/POSIXct vector or function that defines the exact major tic locations along the x axis.
x_minor_breaks	Depending on the class of df$numeric_col, a numeric/Date/POSIXct vector or function that defines the exact minor tic locations along the x axis.
x_labels	A character vector with the same length as 'x_major_breaks', that labels the major tics.
y_limits	A numeric 2 element vector that sets the minimum and maximum for the y axis. Use NA to refer to the existing minimum and maximum.
y_major_breaks	A numeric vector or function that defines the exact major tic locations along the y axis.
y_minor_breaks	A numeric vector or function that defines the exact minor tic locations along the y axis.
y_labels	A character vector with the same length as 'y_major_breaks', that labels the major tics.
axis_text_size	A numeric that sets the font size along the axis'. Default is 11.
pts_color	A string that sets the color of the points.
pts_fill	A string that sets the fill color of the points.
pts_shape	A numeric integer that sets the shape of the points. Typical values are 21 “circle”, 22 “square”, 23 “diamond”, 24 “up triangle”, 25 “down triangle”.
pts_stroke	A numeric that sets the drawing width for a point shape.
pts_alpha	A numeric value that sets the alpha level of pts_color.
pts_size	A numeric value that sets the size of the points.
plot_ref_line	A logical which if TRUE will plot a reference line.
ref_line_color	A string that sets the color of the reference line.
ref_line_width	A numeric that sets the reference line width.
plot_ci_lines	A logical which if TRUE will plot upper/lower confidence lines.
ci_lines_color	A string that sets the color of the confidence lines.
ci_lines_width	A numeric that sets the confidence lines width.
ci_line_type	A string that sets confidence lines line type. Acceptable values are twodash, solid, longdash, dotted, dotdash, dashed
labels_n	A numeric that sets the number of extreme values to label. If NULL then no points are labeled.
label_color	A string that sets the label color.

Value

Returning a ggplot2 object.

Examples

library(ggplot2)
library(data.table)
library(RplotterPkg)
library(RregressPkg)

set.seed(20200825)
sample_obs_df <- data.frame(
  vals = stats::rnorm(20, 10, 3)
)

a_plot <- RregressPkg::plot_qq(
  df = sample_obs_df,
  numeric_col = "vals",
  title = "QQ plot of Random Observations",
  subtitle = "Sample is from a normal distribution",
  x_title = "Theoretical Normal Quantiles",
  y_title = "Sample Quantiles",
  rot_y_tic_label = TRUE,
  ci_lines_color = "blue",
  ci_line_type = "dashed",
  pts_size = 4,
  labels_n = 3
)

deandevl/RregressPkg documentation built on Feb. 5, 2025, 12:11 p.m.