Than you, Gavin. You helped me out a lot of problems. Thank you very much! Wei-Wei
2006/7/12, Gavin Simpson <[EMAIL PROTECTED]>: > On Wed, 2006-07-12 at 00:51 +0800, Guo Wei-Wei wrote: > > Thank you, Gavin. I think that might be what I need. But I'm a little > > bit wandering what's the scale of resid(mod). Is it > > scale(dist)/scale(speed), for example kilometer / (kilometer per > > hour)? or something else? > > > > Thank you very much! > > Wei-Wei > > The scale of dist - they are just the differences between observed dist > and fitted dist (based on speed). > > mod <- lm(dist ~ speed, data = cars) > resid(mod) > > 1 2 3 4 5 > 3.849460 11.849460 -5.947766 12.052234 2.119825 > 6 7 8 9 10 > -7.812584 -3.744993 4.255007 12.255007 -8.677401 > .... > > # visualise the residuals > plot(resid(mod) ~ dist, data = cars) > abline(h = 0, col = "grey") > ## length of blue line represents the residual > lines(cars$dist, resid(mod), type = "h", col = "blue") > > So you see that for the 1st residual it is 3.849 ft (the distances are > measured in feet, see ?cars) > > Does this help? > > G > > > > > > > 2006/7/12, Gavin Simpson <[EMAIL PROTECTED]>: > > > On Tue, 2006-07-11 at 23:51 +0800, Guo Wei-Wei wrote: > > > > Dear all, > > > > > > > > I don't know what's my question is called. I have a performance > > > > variable A, such as sales. And I have another variable B, let's say > > > > establish time of firm. I want to create the third variable that is > > > > sales without the effect of establish time. Maybe it can be called > > > > partial effect problem. I'm not sure. > > > > > > > > Does anyone have any suggestion? Thank you in advance! > > > > > > > > All the best, > > > > Wei-Wei > > > > > > Do you mean? > > > > > > ## dummy data > > > A <- rnorm(100) > > > B <- rnorm(100) > > > C <- resid(lm(A ~ B)) > > > > > > C now contains the residual variation in A after fitting B. > > > > > > e.g. with some real data > > > ?cars > > > data(cars) # not sure this is needed now, I forget > > > mod <- lm(dist ~ speed, data = cars) > > > summary(mod) > > > partial <- resid(mod) > > > > > > ## check > > > mod2 <- lm(dist ~ partial, data = cars) > > > summary(mod2) > > > ## from the two R^2 form mod1 and mod2 - partial contains dist minus > > > ## the effects of speed > > > > 0.6511 + 0.3489 > > > [1] 1 > > > > > > HTH > > > > > > G > > > -- > > > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > > > Gavin Simpson [t] +44 (0)20 7679 0522 > > > ECRC & ENSIS, UCL Geography, [f] +44 (0)20 7679 0565 > > > Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk > > > Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/cv/ > > > London, UK. WC1E 6BT. [w] http://www.ucl.ac.uk/~ucfagls/ > > > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > > > > > > > > > > ______________________________________________ > > R-help@stat.math.ethz.ch mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > -- > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > Gavin Simpson [t] +44 (0)20 7679 0522 > ECRC & ENSIS, UCL Geography, [f] +44 (0)20 7679 0565 > Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk > Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/cv/ > London, UK. WC1E 6BT. [w] http://www.ucl.ac.uk/~ucfagls/ > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
