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using the Aitchson's Method; the tolerance limit is then calculated using the adjusted <br /> values. <br /> Nonparametric Tolerance Limit. When the background data set contains greater than <br /> 50 percent but less than 100 percent nondetect values and/or its distribution is not normal <br /> (or transformed normal), Sanitas applies the nonparametric tolerance limit method. <br /> However, this method requires a large number of samples to achieve a false positive rate <br /> of 1 percent or less, which is the false positive rate required by CCR Title 27. Thus, <br /> nonparametric values are tentative limits only. <br /> Nonstatistical Approach. When the background data set contains 100 percent non-detect <br /> values, Sanitas applies the nonstatistical approach. This approach takes into <br /> consideration that if historically a constituent has not been detected, any detection of that <br /> constituent would be considered an exceedance. Thus, in these situations (100 percent <br /> non-detected values),the tolerance limit is set at"detect", meaning that if a value is <br /> detected above its method detection limit, this value is an exceedance of the <br /> concentration limit. <br /> Foothill WQPS Rev Ldoc <br /> B-2 <br />