This is a great multi-day lesson for higher level biology classes. The activity focuses around a large research project from the University of Washington which studied multiple factors that play into why some people start and keep smoking (addiction). It ties in genes, inheritance, then environment and statistics. Students are able to come up with their own research projects and use the online database to test their hypotheses. At the end, I have students present their results to the class and explain what it means in terms of the biology involved and the math.