Message-ID: <loom.20111208T200640-63@post.gmane.org>
Date: 2011-12-08T19:09:09Z
From: Ben Bolker
Subject: simple fit
R. Michael Weylandt <michael.weylandt <at> gmail.com> writes:
> Fit y-b without an intercept? (which you do by adding "+ 0" or "- 1"
> to the model formula) Not sure if this is the optimal result, but it
> will give you a pretty reasonable answer.
This seems backward. The OP has the slope and wants the intercept.
> On Thu, Dec 8, 2011 at 10:52 AM, Alaios <alaios <at> yahoo.com> wrote:
> > ?I have a formula of the form
> > y=ax+b
> > I know everything except b.
> > How I can ask R to do fitting to find only the value of b?
> > I already know the lm() but it always return both an intercept point
> > (b) and the a.
Or:
lm (y~1,offset=a*x,data= ...)
or
lm(y-a*x~1,data=...) [not sure this will evaluate the full
expresson on the LHS but it might]