iwp.plot {weibullness}

Inverse Weibull Probability Plot

Description

iwp.plot produces an inverse Weibull probability plot.

Usage

iwp.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 inverse Weibull probability plot is based on taking the logarithm of the inverse Weibull cumulative distribution function twice.

Value

A list with the following components:

x

The sorted data

y

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

Author(s)

Chanseok Park

See Also

plot, qqnorm, qqplot, wp.plot.

Examples

 
x = c(0.38, 0.41, 1.2, 0.52, 0.69, 0.89, 0.67, 1.59, 0.55, 0.59)
iwp.plot( x )

# With cosmetic lines 
iwp.plot(x, main="Inverse Weibull Probability Plot", col.line="red", 
        xlab="Lifetimes of bearings", lty.line=1, pch=3)
hline = -log(-log( c( (1:5)/100, (1:9)/10)  ))
abline( h=hline, col=gray(0.1), lty=3, lwd=0.5 )
abline( v=  seq(0, 2,by=0.1), col=gray(0.1), lty=3, lwd=0.5 )