ep.plot {weibullness}

Exponential Probability Plot

Description

ep.plot produces a exponential probability plot.

Usage

ep.plot(x, plot.it=TRUE, a, col.line="black", lty.line=1, 
        xlim=NULL, ylim=NULL, main=NULL, sub=NULL, xlab=NULL, ylab="Probability", ...) 

Arguments

x

a numeric vector of data values. Missing values are allowed.

plot.it

logical. Should the result be plotted?

a

the offset fraction to be used; typically in (0,1). See ppoints.

col.line

the color of the straight line.

lty.line

the line type of the straight line.

xlim

the x limits of the plot.

ylim

the y limits of the plot.

main

a main title for the plot, see also title.

sub

a sub title for the plot.

xlab

a label for the x axis, defaults to a description of x.

ylab

a label for the y axis, defaults to "Probability".

...

graphical parameters.

Details

The exponential probability plot is based on taking the logarithm of the exponential cumulative distribution function.

Value

A list with the following components:

x

The sorted data

y

-log(1-ppoints(n,a=a))

Author(s)

Chanseok Park

See Also

plot, qqnorm, qqplot, wp.plot, iwp.plot.
bs.plot for the Birnbaum-Saunders probability plot in package bsgof.

Examples

 
x = rexp(50)
# With cosmetic lines 
ep.plot(x, main="Exponential Probability Plot", col.line="red", lty.line=1, pch=3)
hline = -log(1- c(0.01,(1:9)/10,0.99))
abline( h=hline, col=gray(0.1), lty=3, lwd=0.5 )
abline( v=seq(0, 5,by=0.5), col=gray(0.1), lty=3, lwd=0.5 )