**Definitions:** There are multiple perspectives on the p-value concept. 1. Assuming that $H_0$ is true, how unusual is the data we have observed. The p-value is the probability of observing the current value or something more extreme. 2. For of a particular [[Statistical Test]] $\psi$, the p-value is the smallest significance level $\alpha$ at which $\psi$ would reject $H_0$. This means that if the p-value is less than our chosen significance level, we reject $H_0$. **Evidence scale:** | p-value | Evidence against $H_0$ | | --------- | ---------------------- | | gt;10\%$ | almost none | | $5-10\%$ | weak | | $1-5\%$ | strong | | $0.1-1\%$ | very strong | | lt;0.1\%$ | undisputable |