[R] dnorm

[Jim Lemon]

On 09/23/2010 05:42 PM, "Sibylle Stöckli" wrote:
> Dear R-users
>
> Idea:
> Plot a dnorm line using specific mean/sd to complete a histogram (skewed). xs:range of y-values, ys: dnorm function
>
> Problem:
> I expected to multiply the ys function with the sample size (n=250-300). I was wondering about a factor between 12'000 and 30'000 to match the size of the dnorm line with the specific histogram.
>
> Thanks
> Sibylle
>
> hist(Biotree[Ld,]$Height2008, main="Larix decidua", ylim=c(0,50), xlab="Tree Height 2008 (cm)",col="aquamarine", font.main=3, cex.axis=0.8)
> xs<-0:650
> ys<-dnorm(xs, mean=397.8, sd=97.6)
> lines(xs,ys*12000)
>
Hi Sibylle,
You can use one of the "rescale" functions (one is in the plotrix 
package) like this:


Ld.hist<-hist(Biotree[Ld,]$Height2008, main="Larix decidua",
  ylim=c(0,50), xlab="Tree Height 2008 (cm)",
  col="aquamarine", font.main=3,cex.axis=0.8)
xs<-0:650
ys<-dnorm(xs, mean=397.8, sd=97.6)
lines(xs,rescale(ys,0:max(Ld.hist)))

Jim