[R] [Plea to the R Gods] Theoretical and Empirical CDFs

[David Winsemius]

On Jun 2, 2011, at 2:18 AM, teriri wrote:

> http://r.789695.n4.nabble.com/file/n3567636/ecdfs.jpg ecdfs.jpg
> http://r.789695.n4.nabble.com/file/n3567636/ecdf_curve.gif  
> ecdf_curve.gif
>
> Hello,
>
> I have generated a plot of two empirical CDFs (attachment 1). As a  
> result,
> they are stepwise when plotted. The following code was used:
>> plot(ecdf(mut), do.points=FALSE, verticals=TRUE, xlim=range(mut,  
>> non),
>> col="red")
>> plot(ecdf(non), do.points=FALSE, verticals=TRUE, add=TRUE,  
>> col="blue")
>
> But what I need instead are smooth curves, similar to ones that are
> generated from a theoretical cdf (attachment 2).
>
> I have looked at so many threads; one suggestion to someone else was  
> to use
> library(fitdistplot) and look for distributions that may fit (e.g.  
> weibull).
> But I could really use guidance before spending additional time on  
> this.

Two threads up in the answer to the question "based on mean and std"  
you might find Ellison's answer useful. You and teriri at gmail.com in  
the same class?

--

David Winsemius, MD
West Hartford, CT