[R] hist() basic question

ripley@stats.ox.ac.uk ripley at stats.ox.ac.uk
Sat Mar 8 19:22:42 CET 2003


A histogram has area one, not sum one.  From ?truehist

Details:

     This plots a true histogram, a density estimate of total area 1. 


On Sat, 8 Mar 2003, juli g. pausas wrote:

> Hi,
> This is a very basic question, but I would like to undestand hist(). I 
> thought that the hist( , freq=FALSE) should provide the relative 
> frequencies (probabilities), and so they should sum 1, however:
> 
> set.seed(2)
> ah <- hist(rnorm(100), freq=F)
> sum(ah$intensities)
> [1] 2
> 
> set.seed(2)
> bh <- hist(rlnorm(100), freq=F)
> sum(bh$intensities)
> [1] 0.4999996
> 
> I'm getting similar figures with truehist() in MASS.
> So I suppose I'm misunderstanding hist(). Any help?
> 
> Thanks
> 
> Juli
> 
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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