14. Precision and Bias
14.1 The precision of the test method was determined by statistical analysis of results obtained an interlaboratory study that included 27 samples including gasolines, distillates,biodiesel,residual oils,and crude oils. A pooled limit of quantitation(PLOQ) of approximately 3 mg/kg S was determined for all sample types. Precision for gasoline and diesel samples,as well as for high-power and low power source XRF instuments is included in Appendix X1. The ranges of sulfur concentrations represented by the sample sets,together with the precisions, are listed in 14.1.1 and 14.1.2 These statistics apply only to samples having less than the level of interfering materials present shown in Table 1 (see also 1.4).