the expected of a probability density function f(x) is given by http://stuff.daniel15.com/cgi-bin/ma...xf%28x%29%20dx

What about http://stuff.daniel15.com/cgi-bin/ma...%7C%20X%3Ea%29 like wise http://stuff.daniel15.com/cgi-bin/ma...%7C%20X%3Ca%29, or even better, what is the general result?