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?
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-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 > PLEASE do read the posting guide 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. [[alternative HTML version deleted]] ______________________________________________ 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.
