Re: [R] Split plot analysis problems

2009-07-23 Thread Jean-Paul Maalouf
Thanks Mark and Richard for your propositions on how to extract residuals. However, I've tried both solutions on my model, and I got different residuals : If we consider the within residuals : Mark's solution gave me a vector of 24 residuals :

Re: [R] Split plot analysis problems

2009-07-23 Thread Mark Difford
Hi Jean-Paul, However, I've tried both solutions on my model, and I got different residuals :... What could be the difference between the two? There is no difference. You have made a mistake. ## tt - data.frame(read.csv(file=tt.csv, sep=)) ## imports your data set T.aov -

Re: [R] Split plot analysis problems

2009-07-22 Thread Jean-Paul Maalouf
Thanks a lot for your answer. My blocks are geographically well-separated, and within each block my four treatments are randomized. Therefore I am choosing the first model. Do you have any idea on how can I verify preliminary assumptions in this model (normality of the residuals and

Re: [R] Split plot analysis problems

2009-07-22 Thread Mark Difford
Hi Jean-Paul, ... since R is not able to extract residuals? R can extract the residuals, but they are a hidden in models with an error structure ## str(aov(PH~Community*Mowing*Water + Error(Block))) residuals(aov(PH~Community*Mowing*Water + Error(Block))$Block)

Re: [R] Split plot analysis problems

2009-07-22 Thread Richard M. Heiberger
Jean-Paul Maalouf wrote: Do you have any idea on how can I verify preliminary assumptions in this model (normality of the residuals and variance homogeneity), since R is not able to extract residuals? Of course, R extracts residuals. Use the proj() function. See ?proj for the example to

[R] Split plot analysis problems

2009-07-21 Thread Jean-Paul Maalouf
Hello, I would be very grateful if someone could give me a hand with my split plot design problems. So here is my design : I am studying the crossed-effects of water (wet/dry) and mowing (mowed/not-mowed = nm) on plant height (PH) within 2 types of plant communities (Xerobromion and

Re: [R] Split plot analysis problems

2009-07-21 Thread Kevin W
I don't think you are clear enough about the layout within each block. If the four treatments are randomized, I would choose the first model. KW On Tue, Jul 21, 2009 at 9:38 AM, Jean-Paul Maalouf jean-paul.maal...@u-bordeaux1.fr wrote: Hello, I would be very grateful if someone could give