[R] Loess Fit

[Greg Snow]

If the client is always right, then what do they need us for?

If you need a function to reproducibly generate predictions, then use loess to generate a set of predictions for a reasonably dense set of x-values, then use approxfun or splinefun to create a function to interpolate for you.  Then this function can give the predictions for various x values.

-- 
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 Thomas S. Dye
> Sent: Monday, November 23, 2009 1:39 PM
> To: Christian Miner
> Cc: r-help at r-project.org
> Subject: Re: [R] Loess Fit
> 
> Thanks Christian.  The client is always right ...
> 
> Tom
> 
> On Nov 23, 2009, at 10:32 AM, Christian Miner wrote:
> 
> > sorry, I don't. I have data that I can estimate, but my client wants
> > to "What if..." 20 separate scenarios, and that requires a function.
> >
> > On Mon, Nov 23, 2009 at 12:22 PM, Thomas S. Dye <tsd at tsdye.com>
> wrote:
> > Hi Christian,
> >
> > Do you have a reference to a publication where this has been done?
> >
> > All the best,
> > Tom
> >
> > On Nov 23, 2009, at 10:15 AM, Christian Miner wrote:
> >
> >> it's a tricky maneuver. When I finish the fit, the predict function
> >> will give me the values, and I can smooth this out so it looks like
> >> a nice non-linear equation. The last thing I need to do is find the
> >> equation, knowing I know have the x and y values, as they will
> >> relate to each other in a non-linear fashion.
> >>
> >> Matlab can do this, but I'd rather not go into that realm.
> >>
> >> On Mon, Nov 23, 2009 at 12:11 PM, Thomas S. Dye <tsd at tsdye.com>
> >> wrote:
> >> Hi Christian,
> >>
> >> I haven't seen an equation associated with a loess fit before.  Do
> >> you have a reference to one of these?
> >>
> >> All the best,
> >> Tom
> >>
> >>
> >> On Nov 23, 2009, at 9:03 AM, Christian Miner wrote:
> >>
> >> 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]]
> >>
> >> ______________________________________________
> >> R-help at r-project.org 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.
> >>
> >>
> >>
> >>
> >> --
> >> Christian Miner
> >> 503-866-6977
> >>
> >
> >
> >
> >
> > --
> > Christian Miner
> > 503-866-6977
> >
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org 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.