ABSTRACT
Control by estimates means direct or indirect control over activities, conditions, operations, or environment by using estimates of important population characteristics. The common methods used to obtain these estimates are probability samples in tests, surveys, or studies, laboratory or field experiments, or some form of 100 percent coverage over a limited time, area, or space. Probability samples are preferable to spot checks or judgment samples because the power of probability and statistics can be brought to bear on the former, but not on the latter.
