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A Comparison of Methods to Deteet Adulteration in Natural Products Under a Restricted Alternative
Author(s) -
Katz B. P.,
Brown M. B.
Publication year - 1989
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.4710310602
Subject(s) - nonparametric statistics , statistics , mathematics , normality , statistic , multivariate statistics , statistical hypothesis testing , test statistic , test (biology) , biology , botany
Multivariate statistical tests used to assess purity of natural food products, such as fruit juices, do not assume prior knowledge about the most likely causes of adulteration. We describe a likelihood ratio test that has a directional alternate hypothesis so that prior knowlege about the most likely method of adulteration can be utilized. Critical regions for this statistic are based on a nonparametric tolerance interval, which makes it insensitive to an assumption of multivariate normality. This new test is compared to two tests currently used for identifying adulterated samples. It is shown that the new test will have increased power relative to the other tests in the direction of the predicted adulteration.