What is "p-value"

n. (context statistics English) In statistical significance testing the p-value is the probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true. (cite journal last=Goodman first = SN year=1999 title = Toward Evidence-Based Medical Statistics. 1: The P Value Fallacy. journal= Annals of Internal Medicine volume=130 pages=995–1004)

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 testing 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 misuse has been a matter of considerable controversy.