p-value
![Example of a p-value computation. The vertical coordinate is the probability density of each outcome, computed under the null hypothesis. The p-value is the area under the curve past the observed data point.](/Images/godic/202502/05/P-value_in_statistical_significance_testing.svg0715.png")
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![Biologist and statistician Ronald Fisher](/Images/godic/202502/05/Biologist_and_statistician_Ronald_Fisher0715.jpg")
In frequentist statistics, the p-value is a function of the observed sample results (a test statistic) relative to a statistical model, which measures how extreme the observation is. Statistical hypothesis tests making use of p-values are commonly used in many fields of science and social sciences, such as economics, psychology, biology, criminal justice and criminology, and sociology. Their use has been a matter of considerable controversy.