[R] Data manipulation

[Roger Peng]

You might want to try subsetting the data frame first, and then fit the
model.  Something like

knap.sub <- knap[c(41:60,81:100,101:120,121:140), ]
knap.fit1 <- lm(Kweed ~ TREAT, data = knap.sub)

might work for you.

-roger
_______________________________
UCLA Department of Statistics
rpeng at stat.ucla.edu
http://www.stat.ucla.edu/~rpeng

On Fri, 7 Feb 2003, Lew wrote:

> I am interested in building a model with a subset of data from a column.
> 
> The first 6 lines of my data look like this:
>     QUAD YEAR SITE TREAT HERB TILL PLANT SEED Kweed 
> 1     A4 2002    s     1    N    N     N    N 55.00   
> 2    A10 2002    s     1    N    N     N    N 60.00   
> 3     B2 2002    s     1    N    N     N    N 35.00  
> 4     C2 2002    s     1    N    N     N    N 23.00   
> 5     C9 2002    s     1    N    N     N    N 70.00   
> 6     11 2002    m     1    N    N     N    N 22.00   
> 
> I tried this command to get the subset I want:
> 
> > knap.fit1<-(lm(Kweed~TREAT[41:60,81:100,101:120,121:140], data=knap))
> No luck.
>  
> Can anyone tell me how to code for this subset.
> 
> Thanks
> 
> Lew Stringer
> M.S. Student- Land Rehabilitation
> Dept. of Land Resources and Environmental Sciences 
> Montana State University
> 822 Leon Johnson Hall
> Bozeman, MT 59717
> Lab:(406)994-6811
> Fax:(406)994-3933
> 
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