Suppose we have two factors, % at I levels and ! at J levels. Let n ij be the number of

,…etc. A

complete layout has n ij $ 1 for all i, j. A balanced layout requires that n

The most general model that may be considered is:

As in the one-way layout, not all the parameters are identifiable. The interaction effect

is interpreted as that part of the mean response not attributable to the additive effect of %

the combination is far superior. In contrast, you may like fish and ice cream, but not together.