SUITABILITY OF SEVERAL STATISTICAL-MODELS TO SIMULATE OBSERVED DISTRIBUTION OF SAMPLE TEST-RESULTS IN INSPECTIONS OF AFLATOXIN-CONTAMINATEDPEANUT LOTS

The acceptability of 10 theoretical distributions to simulate observed distribution of sample aflatoxin test results was evaluated by using 2 parameter estimation methods and 3 goodness of fit (GOF) tests. All theoretical distributions were compared with 120 observed distribution s of aflatoxin test results of farmers' stock peanuts. For a given par ameter estimation method and GOF test, the negative binomial distribut ion had the highest percentage of statistically acceptable fits. The l og normal and Poisson-gamma (gamma shape parameter = 0.5) distribution s had slightly fewer but an almost equal percentage of acceptable fits . For the 3 most acceptable statistical models, the negative binomial had the greatest percentage of best or closest fits. Both the paramete r estimation method and the GOF test had an influence on which theoret ical distribution had the largest number of acceptable fits. All theor etical distributions, except the negative binomial distribution, had m ore acceptable fits when model parameters were determined by the maxim um likelihood method. The negative binomial had slightly more acceptab le fits when model parameters were estimated by the method of moments. The results also demonstrated the importance of using the same GOF te st for comparing the acceptability of several theoretical distribution s.