I have a problem where the crucial variable is the integral of the squared PDF of a random variable, i.e.
$\int f(x)^2dx$
How should I interpret this property of a distribution? If $f(x)$ is gaussian, then this is inversely proportional to the variance, $\sigma^2$, but I don't think this is generally true.
(Note that this is also equal to $\int F(x)f'(x)dx$ ).