In the continuous case, the PDF does not directly depict the actual probability. Instead we define the probability for the stochastic variable to assume any value on an infinitesimal interval around x to be p(x)dx . The continuous function p(x) then gives us the density of the probability rather than the probability itself. The probability for a stochastic variable to assume any value on a non-infinitesimal interval [a,\,b] is then just the integral \begin{equation*} \mathrm{Prob}(a\leq X\leq b) = \int_a^b p(x)dx. \end{equation*} Qualitatively speaking, a stochastic variable represents the values of numbers chosen as if by chance from some specified PDF so that the selection of a large set of these numbers reproduces this PDF.