Null hypothesis

How it is used

Written H₀ and read 'H-nought' or 'H-zero'. Results are phrased as 'reject' or 'fail to reject' the null hypothesis; saying the null is 'accepted' or 'proved' is considered incorrect. Often shortened to 'the null' in speech.

Example sentences

1. The null hypothesis states that the two teaching methods produce the same mean score.

2. With p = .31, we fail to reject the null hypothesis.

Common collocations

• test the null hypothesis
• reject the null hypothesis
• fail to reject the null
• under the null hypothesis

Related terms

• alternative hypothesisThe statement that there is a real effect, difference or relationship; it is the claim a researcher usually expects, and the data support it when they give strong evidence against the null hypothesis.
• reject the null hypothesisTo conclude, after a test, that the data give enough evidence against the null hypothesis, usually because the p-value is below the significance level.
• p-valueThe probability of getting a result at least as extreme as the one observed if the null hypothesis were true; a small value means the data would be surprising under the null.
• significance levelThe threshold, chosen before a test, below which a p-value is treated as statistically significant; it is also the accepted risk of a Type I error.
• type I errorRejecting a null hypothesis that is actually true, in other words concluding that an effect exists when it does not; a false positive.

This word in other fields

The same English word can have a different meaning in another field:

• null hypothesis · Software Engineering
• null hypothesis · Data Science & Analytics

More terms: Hypothesis Testing

• hypothesis
• statistical significance
• t-test
• chi-square test
• ANOVA
• type II error
• statistical power
• degrees of freedom
• two-tailed test
• assumption
• nonparametric test
• post hoc test