lm help: using lm when one point is known (not y intercept)

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Seth Imhoff
Sent: Saturday, November 27, 2004 11:09 PM
To: r-help at stat.math.ethz.ch
Subject: [R] lm help: using lm when one point is known (not y 
intercept)

Hello-

My question is a short one.  How can I specify a single point 
which through the fitted linear model has to go through?  To 
illustrate my problem, the fit to following data must go 
through the point (-37.25(effect), 50(prob)).  Note: you can 
ignore the label column.

    Effect      Prob Label

1 -1143.75  7.142857     L

2  -572.75 21.428571     D

3  -223.75 35.714286    GL

4   123.25 50.000000    DG

5   359.75 64.285714     G

6   374.75 78.571429   DGL

7   821.75 92.857143    DL


Thanks in advance!

Seth Imhoff