Description for Figure 2.1
Nested and non-nested matrix sampling design (c)

Illustration of the nested and non-nested matrix sampling design (c). The nested design is represented with a sample $S$ in a population $U.$ This sample is divided in three subsamples $S_1,S_2$ and $S_3.$ The non-nested design is represented with three independently drawn samples $S_1,S_2$ and $S_3$ from a population $U.$