Scientists use probability and statistics to help quantify how the data they get from experiments or studies are evidence in favor of—or against—a hypothesis. But there is more than one way that statistics can be used to do this job. This video focuses on the debate between two fundamentally different approaches to statistical hypothesis-testing: classical statistics and Bayesian statistics. This video is aligned with Chapter 9 of the book Recipes for Science: An Introduction to Scientific Methods and Reasoning, by Angela Potochnik, Matteo Colombo, and Cory Wright.