| Summary: | 碩士 === 淡江大學 === 統計學系碩士班 === 98 === Risk assessment is usually conducted to evaluate the potential risks from exposure to a single toxic agent. However, people are frequently exposed to multiple chemicals simultaneously or in sequence by different routes from different sources, including, for instance, contaminants in food, drinking water, air, or the environment. Risk assessment for a single researchers to address such question. As a resut, cumulative risk assessment has been received notable interest of researchers in recent years.
Chen et al.(2001) employed the standard logistic model and combine the idea of doseaddition to introduce derived the dose-response function of a chemical mixture for quzntal response. Nevertheless, their dose-response model may not provide a good fit for a given set in some cases. For example, the procedure fails to accyrtly estimate the cumulative risk for combined exposures to multiple chemicals when the dose-response curve are not symmetric or the data have heavy tails. To this end, we proposed an extended doseresponse model for dichotomous response. The approach aim to estimate cumulative risk of the multiple chemicals with common mechanism of toxicity. Confidence interval of the estimated cumulative risk derived from the proposed model was also.
Dose-response model fitted to quantal data can be used not only to predict the probability of response but also to estimate the dose with 100p% response rate, usually called p% effective dose of a toxic chemical and denoted as ED100p. In this study, we propose the two-stage approach to find the mixture effective dose and the optimal individual dose associated with the mixture effective dose.
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