in any test of hypothesis to reject the null hypothesis is to
In inferential statistics, the term "null hypothesis" is a general statement or default position that there is no relationship between two measured phenomena, or no association among groups. Rejecting or disproving the null hypothesis -- and thus concluding that there are grounds for believing that there is a relationship between two phenomena (e.g. that a potential treatment has a measurable effect) -- is a central task in the modern practice of science; the field of statistics gives precise criteria for rejecting a null hypothesis.