Hi Tessa, I agree with John. I think you've made a typo, but looking at
your data I think the zero concentration should not be there. Try plotting
it.

conc = c(10, 20, 30, 40, 50)
signal = c (4, 22, 44, 60, 82)

plot(signal~conc)
abline(lm(signal~conc))


2012/11/9 John Kane <jrkrideau@inbox.com>

> Tessa,
>
> Would you please leave in the context --that is your early remarks and
> mine?
>
> Most of us on the R-help list do no use nabble and it is really annoying
> to have to go there to see what was discussed.  I suspect that a lot of
> readers just don't bother and nabble users lose a lot of possible help that
> way.
>
> In any case, I think your problem  is a typo in the document.
>
>  My first suggestion  gives  exactly the same results shown in the
> document you supplied.  Run this :
> conc = c(0, 10, 20, 30, 40, 50)
> signal = c (4, 22, 44, 60, 82, NA)
> lm.r  <-  lm( signal ~ conc)
> summary(lm.r)
>
> I hope this helps.
> John Kane
> Kingston ON Canada
>
>
> > -----Original Message-----
> > From: tesarants@gmail.com
> > Sent: Fri, 9 Nov 2012 09:36:23 -0800 (PST)
> > To: r-help@r-project.org
> > Subject: Re: [R] lm function - strange error
> >
> > Here is the document
> >
> >
> http://www.montefiore.ulg.ac.be/~kvansteen/GBIO0009-1/ac20092010/Class8/Using%20R%20for%20linear%20regression.pdf
> >
>
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