SkewLaplacePlots {GeneralizedHyperbolic}

Skew-Laplace Quantile-Quantile and Percent-Percent Plots

Description

qqskewlap produces a skew-Laplace QQ plot of the values in y.

ppskewlap produces a skew-Laplace PP (percent-percent) or probability plot of the values in y.

If line = TRUE, a line with zero intercept and unit slope is added to the plot.

Graphical parameters may be given as arguments to qqskewlap, and ppskewlap.

Usage

qqskewlap(y, mu = 0, alpha = 1, beta = 1,
          param = c(mu, alpha, beta),
          main = "Skew-Laplace Q-Q Plot",
          xlab = "Theoretical Quantiles",
          ylab = "Sample Quantiles",
          plot.it = TRUE, line = TRUE, ...)

ppskewlap(y, mu = 0, alpha = 1, beta = 1,
          param = c(mu, alpha, beta),
          main = "Skew-Laplace P-P Plot",
          xlab = "Uniform Quantiles",
          ylab = "Probability-integral-transformed Data",
          plot.it = TRUE, line = TRUE, ...)

Arguments

y

The data sample.

mu

The location parameter, set to 0 by default.

alpha, beta

The shape parameters, both set to 1 by default.

param

Parameters of the skew-Laplace distribution.

xlab, ylab, main

Plot labels.

plot.it

Logical. TRUE denotes the results should be plotted.

line

Logical. If TRUE, a line with zero intercept and unit slope is added to the plot.

...

Further graphical parameters.

Value

For qqskewlap and ppskewlap, a list with components:

x

The x coordinates of the points that are be plotted.

y

The y coordinates of the points that are be plotted.

References

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

See Also

ppoints, dskewlap.

Examples

par(mfrow = c(1, 2))
y <- rskewlap(1000, param = c(2, 0.5, 1))
qqskewlap(y, param = c(2, 0.5, 1), line = FALSE)
abline(0, 1, col = 2)
ppskewlap(y, param = c(2, 0.5, 1))