Continuous Random Variable
Definition
A continuous random variable $X$ is a random variable whose cumulative distribution function $F(x) = \mathbb{P}(X \leq x)$ is continuous. Equivalently, $X$ has a Probability Density Function (PDF) $f$ such that
$$ F(x) = \int_{-\infty}^{x} f(t)\, dt. $$For any single point, $\mathbb{P}(X = x) = 0$.