Create data frame for split-plot design
df.spd(trt.main, trt.sub, label, replicates)a data.frame representing the data structure of the design
an integer-valued vector specifying the treatment structure at
main plot level, similar to df.crd.
an integer-valued vector specifying the treatment structure at
sub plot level, similar to trt.main.
Optional. A list of character vectors, each corresponding to a treatment factor.
The name of each vector specifies the factor's name, and its elements provide the labels for that factor's levels.
If no labels are provided, default labels will be used. For a single treatment factor, the default is
list(trt = c("1", "2", ...)), and for two treatment factors, the default is
list(facA = c("1", "2", ...), facB = c("1", "2", ...)).
For split-plot designs, the defaults are similar but include the ".main" and ".sub" suffixes for main plot and subplot factors.
For example:
list(trt.main = c("1", "2", ...), trt.sub = c("1", "2", ...)) and
list(facA.main = c("1", "2", ...), facB.main = c("1", "2", ...),
facA.sub = c("1", "2", ...), facB.sub = c("1", "2", ...)).
Label sets should be arranged so that the main plot factors come first, followed by the subplot factors.
the number of experimental units (main plots) per treatment of main plot factors.