On Dec 16, 2010, at 11:10 PM, Laura Smith wrote:
Hi!
Here is some output from an str command:
str(CO2)
Classes nfnGroupedData, nfGroupedData, groupedData and
'data.frame': 84 obs. of 5 variables:
$ Plant : Ord.factor w/ 12 levels "Qn1"<"Qn2"<"Qn3"<..: 1 1 1 1 1
1 1 2
2 2 ...
$ Type : Factor w/ 2 levels "Quebec","Mississippi": 1 1 1 1 1 1
1 1 1 1
...
$ Treatment: Factor w/ 2 levels "nonchilled","chilled": 1 1 1 1 1 1
1 1 1 1
...
$ conc : num 95 175 250 350 500 675 1000 95 175 250 ...
$ uptake : num 16 30.4 34.8 37.2 35.3 39.2 39.7 13.6 27.3 37.1 ...
- attr(*, "formula")=Class 'formula' length 3 uptake ~ conc | Plant
.. ..- attr(*, ".Environment")=<environment: R_EmptyEnv>
- attr(*, "outer")=Class 'formula' length 2 ~Treatment * Type
.. ..- attr(*, ".Environment")=<environment: R_EmptyEnv>
- attr(*, "labels")=List of 2
..$ x: chr "Ambient carbon dioxide concentration"
..$ y: chr "CO2 uptake rate"
- attr(*, "units")=List of 2
..$ x: chr "(uL/L)"
..$ y: chr "(umol/m^2 s)"
What do the nfnGroupdata, nfGroupdata mean, please?
Also, what do the attr with formula and outer mean, please?
Per its help page:
help(CO2, package=datasets)
... the answer is probably in Pinheiro, J. C. and Bates, D. M. (2000)
Mixed-effects Models in S and S-PLUS, Springer. Some datasets and
packages are really support material for textbooks, and this appears
to be one such case.
How would I find those things out without posting to the list.
Read the help page?
Do this:
??CO2
--
David Winsemius, MD
West Hartford, CT
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