[R] Controlling the length of line with abline(lm())

[Gabor Grothendieck]

That's normally how its done so you might want to reconsider whether
you really want only the line segment; however, if you insist see ?segments

plot(y ~ x)
y.lm <- lm(y ~ x)
n <- length(x)
# x assumed to be in ascending or descending order
segments(x[1], fitted(y.lm)[1], x[n], fitted(y.lm)[n])


On Wed, Jun 18, 2008 at 10:09 PM, Tariq Perwez <tariq.perwez at gmail.com> wrote:
> Hi
> I just realized that when I use linear regression to draw a line through my
> data points with something like the following:
>
> abline(lm(y ~ x))
>
>
> the length of the line is infinite, i.e., the line goes beyond the smallest
> and the largest data values. This seems not very right to me (not to mention
> it looks unaesthetic). I do not mean to imply that the straight-line
> behavior of my system is maintained throughout. I would like to limit the
> length of this line to the range of my data. However, I have not been able
> to figure out how to. Very disconcertingly, I found out that all the books
> that teach statistics using R seem to be drawing such infinite length-lines.
> I would appreciate any advice or suggestions. Regards,
>
>
> Tariq
>
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>
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