Despite the protestation of Disraeli that, “there are three kinds of lies: lies, damned lies, and statistics,” probably the most important step in any environmental engineering study is the statistical analysis of the results. The principal concept of statistics is that of variation. In conducting typical environmental studies, such as a biological sampling protocol for aquatic organisms, variation is commonly found. Variation comes from the methods employed in the sampling process or, in this example, in the distribution of organisms. Several complex statistical tests can be used to determine the accuracy of data results. In this discussion, however, only basic calculations are reviewed.