dnorm() computes the density, so it may be > 1; pnorm() computes the
distribution function.
--- On Tue, 8/7/08, Mike Lawrence <[EMAIL PROTECTED]> wrote:
> From: Mike Lawrence <[EMAIL PROTECTED]>
> Subject: Re: [R] odd dnorm behaviour (?)
> To: "Rhelp" <[EMAIL PROTECTED]>
> Received: Tuesday, 8 July, 2008, 2:51 PM
> #Let's try this again! This time the code is more
> sensible (curve
> range, same sd value).
>
> #Quick one hopefully. Shouldn't dnorm be returning the
> pdf? Last time
> I checked,
> #a probability shouldn't be greater than 1 as produced
> by:
>
> curve(dnorm(x,0,.1),from=-.5,to=.5)
>
> #Shouldn't I be getting an axis more like that produced
> by:
>
> f=function(x,m,s){
> y=rep(NA,length(x))
> for(i in 1:length(x)){
> y[i]=integrate(
> dnorm
> , upper=x[i]+sqrt(.Machine$double.eps)
> , lower=x[i]-sqrt(.Machine$double.eps)
> , mean=m
> , sd=s
> )$value
> }
> return(y)
> }
> curve(f(x,0,.1),from=-.5,to=.5)
>
> #If the latter code betrays a misunderstanding of what a
> pdf is, be
> gentle!
>
> #Mike
>
> --
> Mike Lawrence
> Graduate Student, Department of Psychology, Dalhousie
> University
>
> www.memetic.ca
>
> "The road to wisdom? Well, it's plain and simple
> to express:
> Err and err and err again, but less and less and
> less."
> - Piet Hein
>
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