# null hypothesis

null hypothesis
noun

The definition of a null hypothesis is a hypothesis that turns out to be incorrect.

An example of a null hypothesis is when you hypothesize that the wind blowing in from the open window was responsible for moving a rock across your desk; but, after testing, you find that wind blowing at the speed at which it was blowing could not move a rock of that size by itself.

## null hypothesis

noun

A hypothesis that is assumed to be true for purposes of statistical testing against an alternative hypothesis. The null hypothesis is usually that there is no treatment effect or no difference between groups.

## null-hypothesis

Noun

(*plural* null hypotheses)

- (statistics) A hypothesis set up to be nullified or refuted in order to support an alternative hypothesis. When used, the null hypothesis is presumed true until statistical evidence in the form of a hypothesis test indicates otherwise. Therefore, the null and the alternative hypothesis must be mutually exclusive and exhaustive. The use of the null hypothesis is controversial.