On Fri, 21 Mar 2008, Luke Spadavecchia wrote: > Hi there, > > I was wondering why > > x<-rnorm(n=5000,mean=1.5,sd=0.25) > h<-hist(x) > sum(h$density) > > [1] 10 > > I thought the integral of the histogram should be one? These seems > strange to me, or am I being silly...
The integral is not a sum of heights but of areas. You need sum(h$density * diff(h$breaks)), and this is spelled out on the help page. > Regards Luke Spadavecchia > > PS. I'm using R 2.5.1 on Mac OSX -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
