Some issues on design and data analysis in practical studies

Many practical projects collect data without a careful study design. This, together with possible inappropriate statistical approaches used in data analysis, may result in questionable study conclusions. A fishery study, which intended to develop the site-specific bioaccumulation factor relationships between the selenium concentration in fish tissue and water, is an example of such projects and partly motivated this thesis project. We analyze the study's data with alternative statistical models to address the concerns raised in the study review by Dr. Carl Schwarz. Further, aiming at providing a useful guideline on data collection, we conduct a simulation study with various settings to explore the efficiency loss in data analysis caused by data incompleteness.