[R] nested repeated measures in R

[Spencer Graves]

	  For nested, repeated measures of normally distributed data, the best 
capability available in R (and perhaps anywhere) is in the 'nlme' 
package.  Excellent documentation is available in Pinheiro and Bates 
(2000) Mixed-Effects Models in S and S-Plus (Springer).  This book is 
also a superlative research monograph by one of the leading contributors 
in this area (Bates) and one of his former graduate students (Pinheiro). 
  If your data are not normal, you may want to use 'lmer' in the 'lme4' 
and 'Matrix' packages;  if you need that, please search the archives for 
more information on that.

	  For help getting data into R, if you have R installed, "help.start()" 
provides easy access to standard documentation shipped with R and 
available without Internet access.  See especially "R Data 
Import/Export" and "An Introduction to R".

	  The simplest way I've found to get data into R is to first store it 
something like "*.csv" or "*.txt" format, plain text with a unique "sep" 
character that is only used to separate fields.  Then I store the file 
name (with the path if different from 'getwd()') in a variable like 
'File'.  Note that "\" is an escape character in R, and to get a 
character interpreted as "\", you must use either "\" or "/".

	  Then I use "readLines" to check the format, including identifying the 
"sep" character.  Then I use "count.fields" to determine the number of 
fields in each record and the number of records.  If I don't get the 
right answer there, I may not have the correct "sep" character.  Or I 
need to read the file in pieces, because of problems in the file.

	  Then I use "read.data".  It has many arguments that can be used to 
modify the "sep" character, skip lines at the beginning of the file and 
then read only a certain number of lines, per the output from 
"count.fields".

	  Hope this helps.
	  Spencer Graves

Doran, Harold wrote:
> You can read the manual, read the FAQs, search the help functions and the archives.
> 
> 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch on behalf of Eric C Merten
> Sent: Fri 7/21/2006 8:51 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] nested repeated measures in R
>  
> R help,
> 
> How would I input data, verify assumptions, and run a nested repeated
> measures ANOVA using R?  I have STATION nested in SITE nested in BLOCK with
> measurements repeated for five YEARs.  All are random variables and it's only
> slightly unbalanced.  I'm trying to characterize spatiotemporal variation in
> stream habitat variables.  Thanks for your help!
> 
> Eric Merten
> 
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