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.