What is a null hypothesis and how is it useful?
A. Null hypothesis: a testable hypothesis that is often formulated on the basis of the simplest set of assumptions 1. In the null hypotheses considered here, the assumptions involve the absence of forces such as selection and drift, and predictions follow only from the assumptions of Mendelian genetics 2. These null hypotheses do not model reality, which is complex, but allow us to see how well real data conform or deviate from the model 3. Deviations from the null hypotheses provide information about processes that must therefore be operating in natural populations 4. Null hypotheses thus allow the formulation of more realistic, well-informed hypotheses based on tested a priori assumptions 5. Hypotheses allow the analysis and reconstruction of models: because nature is complex, it must be broken up into parts (deconstruction) to see how each part or force works on an individual basis, and then we have to figure out how the parts work together in the whole (reconstruction) B. Themes of
