On Sun, 20 Jun 2004, Zhen Chen wrote: > I have problem evaluating the expression h = exp(x)/(exp(exp(x))-1) for > large negative x. This expression is actually the probability > that y = 1 when y is a Poisson random variable truncated at 0, hence > must satisfy 0 <= h <= 1. However, when
You would be better off using the functions provided for the Poisson distribution. Either dpois(1,exp(x))/ppois(0.5,exp(x),lower.tail=FALSE) or to get 1-h ppois(1.5,exp(x),lower.tail=FALSE)/ppois(0.5,exp(x),lower.tail=FALSE) -thomas ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html