fac.design(levels, factor.names=<<see below>>, replications=1,
row.names=<<see below>>, fraction=<<see below>>)
A,
B, etc.
If levels are not given, they default to
the factor name (possibly abbreviated) followed by level numbers.
nrows is the number of observations in the
design.
design object is a data frame,
with variables in the frame corresponding to each of the factors
requested in the design.
In the case that
fraction is specified,
an attribute,
defcon,
will supply the defining contrast(s),
and if
which.half is supplied,
this will also be retained as an attribute.
fac.design chooses defining contrasts
for fractional designs
from a standard list called
dimdc.list.
Avoid using factor names
F
and
T as these can get confused with
FALSE
and
TRUE.
The default factor names skips these two letters.
fnames <- list(react = c("4mod", "5mol"),
acidcon=c("con", "dil"),
acidamt=c("2mol", "2.5mol"),
reactim=c("2", "4"),
reactem=c("low", "high"))
# A 1/4 replicate of a 2^5 design, specifying the -1
# fraction for the first contrast
davies.design <- fac.design(rep(2, 5), factor.names=fnames,
fraction= ~ - react:acidamt:reactim + react:acidcon:reactem)