Critical value
A critical value is the threshold on a test statistic's sampling distribution that marks the boundary of the rejection region at a chosen significance level. If the test statistic exceeds it, the null hypothesis is rejected.
FrameworkHypothesis testing
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On the sampling distribution of the test statistic, the critical value marks where the rejection region begins. For a two-tailed test at α = 0.05 using the standard normal distribution, the critical values are ±1.96, splitting the 5% significance level into 2.5% in each tail. A computed z beyond ±1.96 rejects the null hypothesis.
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SubjectData Analysis & StatisticsCoreTopicHypothesis TestingCore