Conditional probabilities and Bayesian theorem in the study of animal disease introduction. (a didactic approach in environmental risk analysis)

Abstract

Bayesian analysis is one of the topics included in the subject “Environmental Risk Analysis” taught at the Faculty of Agronomy of the University of Buenos Aires, Argentina. Traditionally, we use a tree of probabilities to organize basic concepts necessary to understand this analysis (for example, conditional probability, excluding events, independence, etc.). Then, we deal with concepts of Bayesian analysis (such as additional conditional probability, prior probabilities, posterior probabilities, and their applications). In this work, we propose to analyze the problem method that starts by analyzing the scenarios.•For that, we begin the analysis by paying attention to those events that we are certain have occurred.•We will separate them according to their possible origins and assign them a probability (conditional).•We will then use the probabilities to weight them, and then find a conditional probability of occurrence.