nlPlots: Normal Laplace Quantile-Quantile and Percent-Percent Plots

Description

qqnl produces a normal Laplace Q-Q plot of the values in y.

ppnl produces a normal Laplace P-P (percent-percent) or probability plot of the values in y.

Graphical parameters may be given as arguments to qqnl, and ppnl.

Usage

qqnl(y, mu = 0, sigma = 1, alpha = 1, beta = 1,
     param = c(mu, sigma, alpha, beta),
     main = "Normal Laplace Q-Q Plot",
     xlab = "Theoretical Quantiles",
     ylab = "Sample Quantiles",
     plot.it = TRUE, line = TRUE, ...)
ppnl(y, mu = 0, sigma = 1, alpha = 1, beta = 1,
     param = c(mu, sigma, alpha, beta),
     main = "Normal Laplace P-P Plot",
     xlab = "Uniform Quantiles",
     ylab = "Probability-integral-transformed Data",
     plot.it = TRUE, line = TRUE, ...)

Value

For qqnl and ppnl, a list with components:

x: The x coordinates of the points that are to be plotted.
y: The y coordinates of the points that are to be plotted.

Arguments

y: The data sample.
mu: \(\mu\) is the location parameter. By default this is set to 0.
sigma: \(\sigma\) is the variance parameter of the distribution. A default value of 1 has been set.
alpha: \(\alpha\) is a skewness parameter, with a default value of 1.
beta: \(\beta\) is a shape parameter, by default this is 1.
param: Parameters of the normal Laplace distribution.
xlab, ylab, main: Plot labels.
plot.it: Logical. Should the result be plotted?
line: Add line through origin with unit slope.
...: Further graphical parameters.

References

Wilk, M. B. and Gnanadesikan, R. (1968) Probability plotting methods for the analysis of data. Biometrika. 55, 1--17.

Examples

Run this code

par(mfrow = c(1, 2))
param <- c(2, 2, 1, 1)
y <- rnl(200, param = param)
qqnl(y, param = param, line = FALSE)
abline(0, 1, col = 2)
ppnl(y, param = param)