Beta Random Variable 10/28

$$f(x)=\frac{1}{B(a,b)}x^{a-1}(1-x)^{b-1}, \mbox{ where } B(a,b)=\int_0^1t^{a-1}(1-t)^{b-1}dt$$

This is used for modelling uncertainty for rates of success, as the examples in the book, pages 168-170 show.