replications(formula, data=<<see below>>, na.action=na.fail)
data need not be given, and the formula "~ ." is implied.
data is not given, the search list is used to find the objects in
formula.
Usually a data frame should be attached when
data is not given.
formula.
If all of the levels in each of the terms are replicated the same number
of times, then a vector is returned that contains the number of replicates
for each term.
Otherwise, a list is returned that contains the information on replication,
one component for each term;
an unbalanced main effect will be a vector, an unbalanced two factor
interaction will be a matrix, and so on.
A test for balance is
(!is.list(replications(formula,data))).
replications(post.mean~maskdim*spinsp, wafer) replications(solder[,1:5])