replications(formula, data=NULL, na.action=na.fail)
formula
| a formula or a terms object or a data frame |
data
|
a data frame used to find the objects in formula
|
na.action
| function for handling missing values |
formula
is a data frame and data
is missing,
formula
is used for data
with the formula ~ .
.
A test for balance is !is.list(replications(formula,data))
.
model.tables
## From Venables and Ripley (1997) p.210. N <- c(0,1,0,1,1,1,0,0,0,1,1,0,1,1,0,0,1,0,1,0,1,1,0,0) P <- c(1,1,0,0,0,1,0,1,1,1,0,0,0,1,0,1,1,0,0,1,0,1,1,0) K <- c(1,0,0,1,0,1,1,0,0,1,0,1,0,1,1,0,0,0,1,1,1,0,1,0) yield <- c(49.5,62.8,46.8,57.0,59.8,58.5,55.5,56.0,62.8,55.8,69.5, 55.0, 62.0,48.8,45.5,44.2,52.0,51.5,49.8,48.8,57.2,59.0,53.2,56.0) npk <- data.frame(block=gl(6,4), N=factor(N), P=factor(P), K=factor(K), yield=yield) replications(~. - yield, npk)