Position probability ($\mathrm{Pr}(x\in A)={\int }_A|\psi {|}^{2}dx$)

For a normalized wavefunction $\psi (x)$, the probability of a position measurement lying in a measurable set $A$ is ${\int }_A|\psi (x){|}^{2}dx$. It is a spatial-projection probability and differs from an energy measurement outcome probability.