[R] Add function to histogram?

[Romain Francois]

Le 21.09.2005 10:00, Peter Wolf a écrit :

>Robert Lundqvist wrote:
>  
>
>>Is there any neat way to add a curve (frequency function or the like) to a
>>histogram or other plots? I haven't found one yet...
>>
>>Robert
>>    
>>
>???
>
>dat<-rnorm(100)
>hist(dat,prob=TRUE)
>x<-seq(-3.5,3.5,length=100)
>y<-dnorm(x)
>lines(x,y)
>
>have a look at:  http://cran.at.r-project.org/doc/manuals/R-intro.pdf
>
>Peter Wolf
>  
>
For a frequency polygon, try to work around that piece of code, 
following Peter's notations :

dat <- rnorm(100)
h <- hist(dat,prob=TRUE, border="gray", col="gray90")
diffBreaks <- diff(h$breaks)[1]
xx <- c(h$mids[1]-diffBreaks, h$mids, tail(h$mids,1)+diffBreaks)
yy <- c(0, h$density, 0)
lines(xx, yy, lwd=2)

However, you might prefer (and that's probably wise) the kernel density 
estimator : density() that other people suggested.

Romain

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