Dear Liang Che, > -----Original Message----- > From: liang....@us.pwc.com [mailto:liang....@us.pwc.com] > Sent: Sunday, November 04, 2012 2:12 PM > To: j...@mcmaster.ca > Cc: r-help@r-project.org; 'Sanford Weisberg' > Subject: RE: [R] 95% Q-Q Plot error message > > Thanks John. > > I have one observation data point with a value that's exactly equal to > the predicted value, therefore the residual is 0. Would this be the > reason you mentioned below?
No. An observation with hat-value (leverage) equal to 1 will necessarily have a 0 residual, but the converse isn't true. Are your data a secret? If so, maybe you can make up a suitable example that you can share and that demonstrates the problem. As I said, we'll do what we can in the absence of a reproducible example. John > > > > > > > From: "John Fox" <j...@mcmaster.ca> > To: Liang Che/US/TLS/PwC@Americas-US > Cc: "'Sanford Weisberg'" <sa...@umn.edu>, <r-help@r-project.org> > Date: 11/04/2012 02:03 PM > Subject: RE: [R] 95% Q-Q Plot error message > > ________________________________ > > > > > Dear liang.che, > > I'm guessing that this is the qqPlot() function in the car package. > > This looks to me to be the combination of two problems: (1) You have at > least one observation in your model for which the leverage (hat-value) > is 1. > That could happen, for example, if you have a factor in the model with > only > one observation at a particular level. (2) qqPlot() isn't handling that > degenerate situation properly. > > Not only did I have to guess that you're using qqPlot() in the car > package, > but I had to guess what the problem is. If you read the text from r-help > at > the bottom of your message, you'll see that it says, "provide commented, > minimal, self-contained, reproducible code." If you'd like help beyond > my > remarks above, you're more likely to get it if you provide the commands > and > data for your problem. Of course, we'll take a look at qqPlot() to see > whether it's doing something unreasonable, and fix it if we find a > problem. > > Best, > John > > ----------------------------------------------- > John Fox > Senator McMaster Professor of Social Statistics > Department of Sociology > McMaster University > Hamilton, Ontario, Canada > > > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org <mailto:r-help-boun...@r-project.org> ] > > On Behalf Of liang....@us.pwc.com > > Sent: Sunday, November 04, 2012 1:31 PM > > To: r-help@r-project.org > > Subject: [R] 95% Q-Q Plot error message > > > > Can someone please help with the error message below? > > > > Warning messages: > > 1: Not plotting observations with leverage one: > > 7 > > 2: Not plotting observations with leverage one: > > 7 > > > print(qqPlot(fit),envelop=.95); > > Error in model.frame.default(formula = Y ~ X - 1, drop.unused.levels = > > TRUE) : > > variable lengths differ (found for 'X') > > In addition: Warning message: > > In matrix(yhat, n, reps) : > > data length [9] is not a sub-multiple or multiple of the number of > rows > > [8] > > > > Thanks! > > > > ______________________________________________________________________ > > The information transmitted, including any attachments, is intended > only > > for the person or entity to which it is addressed and may contain > > confidential and/or privileged material. Any review, retransmission, > > dissemination or other use of, or taking of any action in reliance > upon, > > this information by persons or entities other than the intended > > recipient is prohibited, and all liability arising therefrom is > > disclaimed. If you received this in error, please contact the sender > and > > delete the material from any computer. PricewaterhouseCoopers LLP is a > > Delaware limited liability partnership. This communication may come > > from PricewaterhouseCoopers LLP or one of its subsidiaries. > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > <https://stat.ethz.ch/mailman/listinfo/r-help> > > PLEASE do read the posting guide http://www.R-project.org/posting- > <http://www.r-project.org/posting-> > > guide.html > > and provide commented, minimal, self-contained, reproducible code. > > > > > ________________________________ > > The information transmitted, including any attachments, is intended only > for the person or entity to which it is addressed and may contain > confidential and/or privileged material. Any review, retransmission, > dissemination or other use of, or taking of any action in reliance upon, > this information by persons or entities other than the intended > recipient is prohibited, and all liability arising therefrom is > disclaimed. If you received this in error, please contact the sender and > delete the material from any computer. PricewaterhouseCoopers LLP is a > Delaware limited liability partnership. This communication may come from > PricewaterhouseCoopers LLP or one of its subsidiaries. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
