[R] Bug in qnorm or pnorm?

[Trenkler, Dietrich]

I found the following strange behavior  using qnorm() and pnorm():

> x<-8.21;x-qnorm(pnorm(x))
[1] 0.0004638484
> x<-8.22;x-qnorm(pnorm(x))
[1] 0.01046385
> x<-8.23;x-qnorm(pnorm(x))
[1] 0.02046385
> x<-8.24;x-qnorm(pnorm(x))
[1] 0.03046385
> x<-8.25;x-qnorm(pnorm(x))
[1] 0.04046385
> x<-8.26;x-qnorm(pnorm(x))
[1] 0.05046385
> x<-8.27;x-qnorm(pnorm(x))
[1] 0.06046385
> x<-8.28;x-qnorm(pnorm(x))
[1] 0.07046385
> x<-8.29;x-qnorm(pnorm(x))
[1] 0.08046385
> x<-8.30;x-qnorm(pnorm(x))
[1] -Inf


Given that pnorm(8.30) delivers 1 shouldn't we get Inf 
for  x<-8.30;x-qnorm(pnorm(x)) ?

Thanks in advance.

Dietrich Trenkler

--
Dietrich Trenkler   Universität Osnabrück                                  
FB Wirtschaftswissenschaften           
Rolandstr.8              D-49069 Osnabrück

dtrenkler at nts6.oec.uni-osnabrueck.de