Add function to histogram?

Le 21.09.2005 10:00, Peter Wolf a ??crit :

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

visit the R Graph Gallery : http://addictedtor.free.fr/graphiques
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