Grass: Yields from Nitrogen nutrition of grass species
Description
The data frame Grass gives the yield (10 * log10 dry-weight (g))
of eight grass Species in five replicates (Block) grown in sand culture
at five levels of nitrogen.
Usage
data(Grass)
Arguments
source
Gittins, R. (1985), Canonical Analysis: A Review with Applications in Ecology,
Berlin: Springer-Verlag, Table A-5.
Details
Nitrogen (NaNO3) levels were chosen to vary from what was expected to be from
critically low to almost toxic. The amount of Nitrogen can be considered on
a log3 scale, with levels 0, 2, 3, 4, 5. Gittins (1985, Ch. 11) treats these
as equally spaced for the purpose of testing polynomial trends in Nitrogen level.
The data are also not truly multivariate, but rather a split-plot experimental design.
For the purpose of exposition, he regards Species as the experimental unit, so
that correlations among the responses refer to a composite representative of a species
rather than to an individual exemplar.