null hypothesis
Assumed no effect
The null hypothesis is the default assumption in statistical testing—typically that no effect, difference, or relationship exists.
Researchers design experiments to reject the null hypothesis, thereby supporting an alternative.
If you test whether a drug works, the null hypothesis is that it doesn't: The data failed to reject the null hypothesis.
Often shortened to the null.
Probability under null hypothesis
- alphaFirst Greek letter
- rejectDismiss as unsuitable
- type I errorRejecting a true null
- type II errorFailing to reject falsity
false positive · false negative · confidence interval · sample size
Unverified belief accepted as true
- status quoExisting condition of affairs
- starting pointPlace of commencement
- presumptionBelief held without proof
- premiseFoundation for logical argument
no effect · unchanged · reference point · benchmark · random chance
Facts supporting truth
- statistical significanceUnlikely due to chance
- scientific methodStructured process for investigation
- falsificationDeliberate alteration of truth
- burden of proofDuty to prove allegations
p-value
Probability under null hypothesis
- alphaFirst Greek letter
- rejectDismiss as unsuitable
- type I errorRejecting a true null
type II error · false positive · false negative · confidence interval · sample size
assumption
Unverified belief accepted as true
- status quoExisting condition of affairs
- starting pointPlace of commencement
- presumptionBelief held without proof
no effect · premise · unchanged · reference point · benchmark · random chance
evidence
Facts supporting truth
- statistical significanceUnlikely due to chance
- scientific methodStructured process for investigation
- falsificationDeliberate alteration of truth
- experimentsexperiment, experiments, test, tests, trials
- research methodsexperiment, deduction, experiments, induction, scientific method
- scientific methodexperiment, theory, data, observation, prediction
- statisticsmean, median, mode, variance, standard deviation
- hypothesesconjecture, supposition, postulate, assumption, premise
- biostatisticsANOVA, biostatistics, t-tests, confidence interval, p-value