linear model and by()

Hello R list,

snipped answered question

Sorry to not use your data but it's not in a form that lends itself  
very well to quick testing. If you had included the input commands I  
might have tried it.

No problem not use my data. For future reference, would it have been  
easier to attach a .csv file and then include the appropriate  
read.csv command? I realized that the easier one makes it to help,  
the easier it is to get a response.

The Posting Guide suggests you include dump("x", file=stdout())

I have a simple x object in my workspace:

 > dump("x", file=stdout())
x <-
c(0, 0, 1, 1, 1, 1)

After reading again the Posting Guide, I am not sure about csv  
attachments, but I can try a simple test. I am removing your address  
(which probably would have accepted the attachment) and leaving only  
the r-help address. If you see an attachment then csv's are accepted.

snipped earlier data

-- 
*****************************************************
Sam Albers
Geography Program

David Winsemius, MD
Heritage Laboratories
West Hartford, CT