Inspection of Commercial Fertilizers 2010 January 1 through ...

to give an average of 5.1 percent. A second series, perhaps from a different manufacturer, analyzed5.1, 5.1, 5.1, 5.1 and 5.2 percent nitrogen for an average of 5.1 percent. Although the average wasidentical the range or "scatter" is much less in the second series. The "Coefficient of Variation" is ameasure of this scatter. It is an expression of the standard deviation in terms of the average. Thefirst series has a high coefficient of variation while the second series has a low coefficient of variation.Thus, a small coefficient of variation indicates the manufacturer has good production control. Thecoefficients of variation shown in Table 3 were calculated from all samples including those which passedas well as those that did not meet guarantee.7