[R] Loess Fit

[Greg Snow]

Check out the loess.demo function in the TeachingDemos package.  Using this function with your data will show the scatterplot with the loess curve.  Then if you click in the plot it will show the line/curve used to do the prediction for that x-value, click on another x-value and you will see that the line/curve used there is different from before.  There is not a single function created by the loess algorithm, rather a different approximation for every possible x-value (theoretically infinite, practically still a big number).

You could fit a function to the results of loess (or approximate the points with a function), but the function will probably be complicated enough that it would not tell you much that the points themselves don't.

-- 
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 Christian Miner
> Sent: Monday, November 23, 2009 12:04 PM
> To: r-help at r-project.org
> Subject: [R] Loess Fit
> 
> I'm working on Loess fit models using R, once I have the fit
> accomplished,
> I'm looking to back-out the equation of the fitted non-linear curve,
> wondering if there is a way to determine this equation in R? I've been
> looking but can't find any literature. For me, the graph of the
> function is
> great, but without the equation of the graph, I'm kinda dead in the
> water.
> 
> Christian Miner
> 503-866-6977
> 
> 	[[alternative HTML version deleted]]
> 
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