Testing Hypotheses in Particle Physics: Plots of p₀ Versus p₁

For situations where we are trying to decide which of two hypotheses $H_{0}$ and $H_{1}$ provides a better description of some data, we discuss the usefulness of plots of $p_{0}$ versus $p_{1}$, where $p_{i}$ is the $p$-value for testing $H_{i}$. They provide an interesting way of understanding the difference between the standard way of excluding $H_{1}$ and the $CL_{s}$ approach; the Punzi definition of sensitivity; the relationship between $p$-values and likelihood ratios; and the probability of observing misleading evidence. They also help illustrate the Law of the Iterated Logarithm and the Jeffreys-Lindley paradox.