[R] two densities with same stepsize

[Greg Snow]

Duncan told you how to do this using density, another option is to use
the logspline package for a different way to estimate densities.  With
this approach you can use the dlogspline and plogspline functions to
compare your density estimates.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
(801) 408-8111
 
 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Antje
> Sent: Tuesday, February 05, 2008 1:22 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] two densities with same stepsize
> 
> Hi there,
> 
> I have two series of data. plotting the density function of 
> both gives me an idea about the difference of the data. But I 
> would like to quantify the difference I see.
> 
> a <- rnorm(100)
> b <- rnorm(100)
> 
> da <- density(a)
> db <- density(b)
> 
> The problem is that da$x and db$x are different and so I have 
> difficulties to compare them... Is there any way to force the 
> density funtion to produce the values for the same x-steps?
> Or is there any other statistical approach I should use for 
> comparing two density functions? I need to quantify how much 
> the data-series differ (density function is rather complex in 
> my case with skew and several maximas, so not easily to 
> describe as a mathematical function.
> Sorry, I'm not that deep into statistics. Any comments / 
> keywords on this is welcome...
> 
> Antje
> 
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