1 1 vote $X$ is a random variable with density Then $E(|X|)=$________ Probability goclasses_da_probability_wq8 numerical-answers goclasses goclasses-testseries-2026 one-mark probability + – GO Classes 358 views answer comment Share Follow Print 0 reply Please log in or register to add a comment.
4 4 votes Solution. We have $$ E(|X|)=\int_{-\infty}^{\infty}|x| \frac{1}{4} e^{-|x| / 2} \mathrm{~d} x=2 \int_{0}^{\infty} x \frac{1}{4} e^{-x / 2} \mathrm{~d} x=\int_{0}^{\infty} x \frac{1}{2} e^{-x / 2} \mathrm{~d} x=2 $$ where the last equality follows by observing that the integral is nothing but the expected value of an exponentially distributed random variable with mean 2 . GO Classes answered Jun 27, 2025 GO Classes comment Share Follow 0 reply Please log in or register to add a comment.