Statistical Sampling Strategies for Survey of Soil Contamination - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 170

this control the precision of the estimated parameters of the SCDF. Note that by not
using the sub-areas as strata in sampling, the number of sampling locations within
a given sub-area is not fixed, but random, i.e. it varies between samples drawn with
the same sampling design.
Figure 4.1 illustrates a STSI sample of 100 locations for estimating the SCDF
of 252 chemical compounds in the topsoil (0-10 cm) and subsoil (50-100 cm)

Fig. 4.1 (continued)