[R] problems with rexp ?

Uwe Ligges ligges at statistik.uni-dortmund.de
Fri May 3 16:07:47 CEST 2002

Juan Ramon Gonzalez wrote:
> Does anyone know if R have any problems with the exponential random number
> generation (function rexp)?
> I comment it because I executed
> data<-sort(rexp(100))
> plot(data,dexp(data)/(1-pexp(data)),type="l")
> and the graphic isn't constant.
> (Note: exponential distribution have a constant hazard failure rate).

Well, plot() scales the "y"-values to fit best into the area:

 data <- sort(rexp(100))
 dexp(data)/(1-pexp(data))      # all 1 ???
 dexp(data)/(1-pexp(data)) - 1  # almost !!

>From the computational point of view everything is looking very well,
isn't it?
Maybe you would like to set a ylim as in

 plot(data,dexp(data)/(1-pexp(data)),type="l", ylim =c(0,2))

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