Detecting hormesis using a non-parametric rank test

Abstract

When a dose-response experiment is conducted, the enhanced responses can be observed at low doses. This phenomenon is often called hormesis. The enhanced responses at low doses does not necessarily mean the existence of hormesis. It is important to conduct statistical analyses to determine whether a departure from monotonic relationships is significantly different from the chance occurrence. This paper introduces a non-parametric rank testto detecthormesis. To illustrate the use ofthis method, we apply it to the data from a Whole Effluent Toxicity test. We demonstrate that the occurrence of hormesis can be statistically evaluated by using this non-parametric rank test.

Keywords

dose response hormesis non-parametric rank test umbrella hypothesis Whole Effluent Toxicity

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