Homework Statement
The mean of a function is as follows:
$${1 \over {a - b}}\int_b^a {f(x)\,dx} $$
So why is the mean of the PDF as follows:
$$\int_{ - \infty }^\infty {xf(x)\,dx} $$
I thought it would have been this way:
$$\lim \,b \to - \infty \,{1 \over { - b}}\int_b^0...