What do you actually know? You don't have `known errors', as if you did you could correct the values. I doubt if you actually have a known range, more likely a standard error or a confidence interval. (If you think you do have a known range, how do you know?)
And if A is not known exactly, linear regression is not fully appropriate. If you know standard errors, then you need a homoscedastic errors-in-variables formulation. One early account is Ripley, B. D. and Thompson, M.(1987) Regression techniques for the detection of analytical bias. Analyst 112, 177-183. and its Fortran program is still available, and although I have never coded it in R, I believe others have. On Sun, 9 May 2004, Sebastian Schubert wrote: > I'm now to R and hope (actually, I'm quite sure) you can help me. I made > an experiment and measured two values. As I know the errors of these > values I want to use them with the linear regression, > eg > Value A > 1.1+-0.02 > 1.9+-0.05 > 3.05+-0.03 > 4.0+-0.01 > 5.1+-0.06 > > Value B > 4.2+-0.14 > 5.3+-0.05 > 6.8+-0.11 > 7.9+-0.01 > 8.5+-0.02 > > lm(B~A) does the linear regression but how can I use the fact that 1.1 is > between 1.12 and 1.08? > How can I put error bars for A and B in the plot (like Excel is capable > of)? Many ways, for example using arrows() or plotCI in package gregmisc. > I hope I made myself understandable, > thanks > Sebastian -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
