Analysis of variance; comparing models

Note that aov() has not been implemented.

The model fitting function aov(formula, data= data.frame) operates at the simplest level in a very similar way to the function lm(), and most of the generic functions listed in Table  apply.

It should be noted that in addition aov() allows an analysis of models with multiple error strata such as split plot experiments, or balanced incomplete block designs with recovery of inter-block information. The model formula

response I<>mean.formula + Error(strata.formula)

specifies a multi-stratum experiment with error strata defined by the strata.formula. In the simplest case, strata.formula is simply a factor, when it defines a two strata experiment, namely between and within the levels of the factor.

For example, with all determining variables factors, a model formula such as that in:

fm <- aov(yield v + n*p*k + Error(farms/blocks), data=farm.data)

would typically be used to describe an experiment with mean model v + n*p*k and three error strata, namely ``between farms'', ``within farms, between blocks'' and ``within blocks''.