ABSTRACT
The above rule is especially helpful in acreage and yield surveys of crops, when a sample of fields (or farms or plots) is selected with probability proportional to total (geographical) area in each stratum. If the number of sample units allocated to a stratum is made proportional to the total geographical area of the stratum, the design becomes self-weighting as Yhi/Zhi (the proportion of the area under the crop or the crop-yield per unit area) can be observed easily (sections 11.4 and 12.3.8).
