plotNormalDensity: Density plot with a normal curve

In rcompanion: Functions to Support Extension Education Program Evaluation

Density plot with a normal curve

Description

Produces a density plot for a vector of values and adds a normal curve with the same mean and standard deviation. The plot can be used to quickly compare the distribution of data to a normal distribution.

Usage

plotNormalDensity(
  x,
  col1 = "white",
  col2 = "gray",
  col3 = "blue",
  border = NA,
  main = "",
  lwd = 2,
  length = 1000,
  adjust = 1,
  bw = "nrd0",
  kernel = "gaussian",
  ...
)

Arguments

x	A vector of values.
col1	The color of the density plot. Usually not visible.
col2	The color of the density polygon.
col3	The color of the normal line.
border	The color of the border around the density polygon.
main	The title displayed for the plot.
lwd	The width of the line in the plot.
length	The number of points in the line in the plot.
adjust	Passed to density. A lower value makes the density plot smoother.
bw	Passed to density.
kernel	Passed to density.
...	Other arguments passed to plot.

Details

The function plots a polygon based on the density function. The normal curve has the same mean and standard deviation as the values in the vector.

Value

Produces a plot. Returns nothing.

Author(s)

Salvatore Mangiafico, [e-mail]

References

https://rcompanion.org/handbook/I_01.html

See Also

plotNormalHistogram, plotDensityHistogram

Examples

### Plot of residuals from a model fit with lm
data(Catbus)
model = lm(Steps ~ Gender + Teacher,
           data = Catbus)
 plotNormalDensity(residuals(model))          

rcompanion documentation built on Sept. 17, 2023, 5:07 p.m.