Jesus and the rest of the R-help community:
Thanks for your help. I have been going over and over the examples in MASS and the Pinheiro and Bates example, but cannot get my model to run correctly with either aov or lme. Could someone give me a hand with the correct model statement?
First a description of the design. We are studying germination rates for various species under a variety of treaments. This is a blocked split-split plot design. The levels and treatments are:
Blocks: 1-6
Whole plot treatment: Overstory: Yes or No
Split plot treatments: Caging (to protect against seed predators): Yes or No Herbaceous competition (i.e., grass): Yes or No
Split-split plot treatment: Tree species: 7 kinds
The response variable is Lag, which is a indication of when the seeds first germinated. I will be doing this analysis for a couple other response variables as well in separate analyses.
I have had mixed results using the examples as a guide to build my statement; I am unsure how to specify the crossed factors at the split-plot level.
Lastly, I have unbalanced data since some treatment combinations never had any germination. Since the data are highly nonnormal, I hope to do a permutations test on the F-values for each main effect and interaction in order to get my p-values.
Thanks for your help in advance, Mike
Mike Saunders Research Assistant Forest Ecosystem Research Program Department of Forest Ecosystem Sciences University of Maine Orono, ME 04469 207-581-2763 (O) 207-581-4257 (F)
----- Original Message -----
From: "Jesus Frias" <[EMAIL PROTECTED]>
To: "Mike Saunders" <[EMAIL PROTECTED]>; "R Help" <[email protected]>
Sent: Tuesday, February 01, 2005 10:57 AM
Subject: RE: [R] Split-split plot ANOVA
Hi Mike,
*An example of the use of aov() for a split-plot is in MASS
library(MASS) example(Oats) The book also gives a detailed explanation
*pp 45-52 of the Pinheiro and Bates book gives you an example of the use of lme() on a split-plot. If you have a non balanced design, lme() from the nlme library might be a better tool than aov().
Also, if you have the lme4 library installed you'll have a lot more flexibility on the formulation of your random effects.
regards,
Jesus
-------------------------------------------------------------- Jes�s Mar�a Fr�as Celayeta School of Food Sci. and Env. Health. Faculty of Tourism and Food Dublin Institute of Technology Cathal Brugha St., Dublin 1. Ireland t +353 1 4024459 f +353 1 4024495 w www.dit.ie/DIT/tourismfood/science/staff/frias.html --------------------------------------------------------------
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Mike Saunders Sent: 01 February 2005 14:36 To: R Help Subject: [R] Split-split plot ANOVA
Does someone out there have an example of R-code for a split-split plot ANOVA using aov or another function? The design is not balanced. I never set up one in R before and it would be nice to see an example before I tackle a very complex design I have to model.
Thanks, Mike
Mike Saunders Research Assistant Forest Ecosystem Research Program Department of Forest Ecosystem Sciences University of Maine Orono, ME 04469 207-581-2763 (O) 207-581-4257 (F)
[[alternative HTML version deleted]]
______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
-- This message has been scanned for content and viruses by the DIT Information Services MailScanner Service, and is believed to be clean. http://www.dit.ie
-- This message has been scanned for content and viruses by the DIT Information Services MailScanner Service, and is believed to be clean. http://www.dit.ie
______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
