[R] Can't mix high level and low level plot functions.
Lothar Botelho-Machado
r-help at botelho-machado.de
Mon Sep 25 23:08:16 CEST 2006
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Thanks for your help!!
I appreciate, now it works perfectly.
Lothar Rubusch
Duncan Murdoch wrote:
> On 9/25/2006 1:56 PM, Lothar Botelho-Machado wrote:
>> Hey R-Comunity,
>>
>>
>> I'd like to print out an histogram of some experimental data and add a
>> smooth curve of a normal distribution with an ideally generated
>> population having the same mean and standard deviation like the
>> experimental data.
>>
>>
>> The experimental data is set as vector x and its name is set to
>> group.name. I paint the histogram as follows:
>>
>> hist(data, freq=FALSE, col="lightgrey", ylab="Density", xlab=group.name)
>>
>>
>>
>> First I did the normal distribution curve this way:
>>
>> lines(x, dnorm(x, mean=mean(x), sd=sd(x)), type="l", lwd=2)
>>
>> This curve just uses as many values as there are in x. When using small
>> amounts of sample populations the curve looks really shaky.
>
> This is generally the right way to do it, but you likely want to use a
> different variable for the first two occurrences of x, e.g.
>
> x0 <- seq(from=min(x), to=max(x), len=200)
> lines(x0, dnorm(x0, mean=mean(x), sd=sd(x)), type="l", lwd=2)
>
> Duncan Murdoch
>
>>
>>
>> I tried this one using a high level plot function as well:
>>
>> curve(dnorm, n=10000, add=TRUE, xlim=range(x))
>>
>> The advantage is, now I can set an ideal population of 10000 to get the
>> ideal curve really smooth. But the big disadvantage is, I don't know how
>> to add "mean=mean(x), sd=sd(x)" arguments to it? It says that it can't
>> mix high level with low level plot functions when I try to set some kind
>> of parameter like "n=10000" to the low level function, it says that
>> there ain't enough x values.
>>
>> So my question is, how to get a smooth curve placed of dnorm over an
>> histogram of sample data, ideally by using the curve method?
>>
>>
>> TIA,
>> Lothar Rubusch
>>
>> ______________________________________________
>> R-help at stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
iD8DBQFFGEVAHRf7N9c+X7sRAtRoAJ97ft75u1etTac3Daiti1u2mlyRWgCeIAAK
81WfyDGzDdWDm11MwPiDKIA=
=W2m9
-----END PGP SIGNATURE-----
More information about the R-help
mailing list