Definition of "null hypothesis" []

• 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. (noun)

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• "It would be more parsimonious, Simberloff argued, to entertain a null hypothesis before seizing on the hypothesis of competition."
• "In 1697, a Dutch sea captain chanced upon a black swan in Australia, at which point the null hypothesis was proven true and the white swan theory had to be discarded."