Sequential method of estimating the LD50 using a modified up-and-down rule.
In this paper, the original up-and-down method, modified up-and-down method, the Robbins-Monro method, and a fixed-sample Spearman-Kärber method are compared for the point estimator as well as the confidence interval of LD50. In particular, three different designs of the modified up-and-down approach based on the combination of experiments on one test space and reduced test space are investigated. The standard normal distribution and chi-square distribution are used as tolerance distributions. Simulation results indicate that the modified up-and-down method tends to be somewhat better than the original up-and-down method in terms of the mean squared error under normal tolerance distribution. In case of chi-square distribution, the modified method is shown to be substantially better when the test space is wide and the initial dose is further away from the LD50.
Department of Biostatistics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0032.
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Jung
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Choi
D007928:Lethal Dose 50; D008432:Mathematical Computing; D011789:Quantum Theory; D013223:Statistics as Topic / Q000379:methods*; D014116:Toxicology / Q000379:methods*