Number of Replications of Terms

DESCRIPTION:

Returns a vector or a list of the number of replicates for each term in the formula.

USAGE:

replications(formula, data=<<see below>>, na.action=na.fail) 

REQUIRED ARGUMENTS:

formula
a formula, a terms object, or a design. If a design, then data need not be given, and the formula "~ ." is implied.

OPTIONAL ARGUMENTS:

data
a design or data frame. If 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.
na.action
function that specifies how missing values are handled.

VALUE:

a vector or a list whose length is the number of terms in 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.

DETAILS:

A test for balance is (!is.list(replications(formula,data))).

SEE ALSO:

, .

EXAMPLES:

replications(post.mean~maskdim*spinsp, wafer) 
replications(solder[,1:5])