Statistics investigates and develops specific methods for evaluating hypotheses in the light of empirical facts. A method is called statistical, and thus the subject of study in statistics, if it relates facts and hypotheses of a particular kind: the empirical facts must be codified and structured into data sets, and the hypotheses must be formulated in terms of probability distributions over possible data sets. The philosophy of statistics concerns the foundations and the proper interpretation of statistical methods, their input, and their results.  Since statistics is relied upon in almost all empirical scientific research, serving to support and communicate scientific findings, the philosophy of statistics is of key importance to the philosophy of science. It has an impact on the philosophical appraisal of scientific method, and on the debate over the epistemic and ontological status of scientific theory.