Null hypothesis

Claim that an investigator desires to disprove.

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