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A STATISTICAL EVALUATION OF OHMSETT TESTING
Citation:
Foster, D., S. Schwartz, AND G. Smith. A STATISTICAL EVALUATION OF OHMSETT TESTING. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-81/124.
Description:
This program was initiated to provide a statistical evaluation of performance data generated at the USEPA's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT). The objective was to investigate the value of replicate testing in developing efficient test programs giving the maximum reliable information from the minimum number of tests. This study was set up in two separate programs, each consisting of 24 tests: one program where 24 different conditions were tested and a second program where three replicates each of eight different conditions were tested. A comparison was then possible between the two types of programs. The 3-replicate test matrix was duplicated to produce six replicates and the validity of the non-replicate and 3-replicate programs was evaluated with respect to the 6-replicate data. Parameters affecting device performance studied in this program were tow speed, wave condition, oil type, and oil slick thickness. These parameters were tested at various levels, with device performance evaluated in terms of throughput efficiency (the ratio of oil collected to oil encountered). Comparisons between point estimates and confidence intervals, graphic trend analysis, and analysis of variance were all examined. The results of this program indicate a need for replicate testing to provide accurate estimates of performance parameters, significant effects and performance trends.