A statistical procedure to evaluate clean‐up standards

The object of this paper is to develop a suitable statistical procedure to evaluate clean‐up standards at hazardous waste sites. Under the assumptions that contaminant masses at a site follow a gamma distribution and that the data from the pre‐remediation baseline sample as well as from the interim or final sample taken after a certain period of operation are both distributed as gamma with the same shape parameter but different scale parameters, we derive a uniformly most powerful unbiased test of the hypothesis that a specified percentage of contaminant mass has been reduced. A large‐sample approximation of the exact test procedure and a comparison with the likelihood ratio test are provided.