# P-value P-value is a probability value that essentialy quantifies the probability of commiting a *Type I error*. In other words, it quantifies the probability that given the null hypothesis $H_0$ is true, you conclude that the alternative hypothesis $H_1$ is the truth. In other words, you conclude the defendent is guilty given that in reality they are innocent. The P-value is - A measure of **false positives** >[!Abstract] In statistics, this “how often” is called “p-value”. The p-value is the probability of observing the value of the calculated test statistic under the null hypothesis assumptions. Usually, the p-value is assessed relative to some predetermined level of significance (0.05 is often chosen) ## Relations - [[p-hacking]] - [[AB Testing|AB Testing]] - [[Power Analysis|Statistical Power]] - [[Type I and Type II Errors]]