ABSTRACT
This chapter introduces the two–factor nested design with factor B nested within factor A. In experiments that involve several factors some factors might be crossed and others might be nested. Such designs that involve both crossed and nested factors are often called nested–factorial experiments. In some experiments replications are obtained by taking several observations on the same experimental units. Observations of this type are referred to as subsamples and the process of obtaining the observations is called subsampling. While subsampling often occurs in nested designs, it can also occur in other designs. In experiments involving subjects it is often the case that multiple observations are made upon the same subject. Subsampling is an important concept used in developing a design for an experiment. It provides a method for obtaining additional experimental observations.
