Null hypothesis

In scientific research, the null hypothesis (often denoted H₀) is the claim that the effect being studied does not exist. Note that the term "effect" here is not meant to imply a causative relationship.

The null hypothesis can also be described as the hypothesis in which no relationship exists between two sets of data or variables being analyzed. If the null hypothesis is true, any experimentally observed effect is due to chance alone, hence the term "null". In contrast with the null hypothesis, an alternative hypothesis is developed, which claims that a relationship does exist between two variables.