weibullness (version 1.24.1)

iwp.plot: 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", ...)

Value

A list with the following components:

x

The sorted data

y

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

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.

Author

Chanseok Park

Details

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

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 )