Exponential Distribution¶ Probability Density Function¶ \[f_X(x)=\begin{cases} \lambda e^{-\lambda x},&\quad x\geq0\\ 0,&\quad x<0 \end{cases}\] Expectation¶ \[\mathbb{E}[X]=\frac{1}{\lambda}\] Variance¶ \[\mathrm{var}(X)=\frac{1}{\lambda^2}\]