Message-ID: <11954C8B-30AE-477D-9BF9-3E103E4912DA@comcast.net>
Date: 2009-03-04T18:49:28Z
From: David Winsemius
Subject: best fit line
In-Reply-To: <22336095.post@talk.nabble.com>
On Mar 4, 2009, at 1:22 PM, anujgoel wrote:
>
> Dear R Community,
> I am plotting this simple x-y plot (raw data & plot attached).
> I cant fit a linear regression line to it. I have to figure out what
> is the
> best fit for this graph.
That is virtually impossible to define rigorously. The "best fit"
would go through all the points precisely, the extreme form of
overfitting, but the mathematical result would not be informative at
all. Where did these data come from? What domain of science are you
working on? You want a result that incorporates the relationships
known to exist in your domain of investigation and summarizes the data
without overfitting. I am being intentionally vague in what follows
because this looks like homework.
> Is there a way to tell which regression to use for
> this kind of data?
Not really. Looks rather "hyperbolic", so you might think about the
formula for hyperbola and then use the lm function.
>
> Also, after selecting the best fit model, I need to extrapolate what
> could
> be the other possible data points.
The predict functions are used for this purpose. Consult you
documentation.
?predict
--
David Winsemius
>
> I am new to R. Could anyone please help?
> Thanks.
> Anuj
> http://www.nabble.com/file/p22336095/plot.jpg
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