medium   Probability

Absolute Normal Difference

A release-checked medium problem for training Expected Value, Continuous Random Variables, Calculus.

Question

We have $X \sim N(0,1)$ and $Y \sim N(0,4)$ are independent. Compute $\mathbb{E}[|Y - X|]$. The answer will be in the form $\left(\dfrac{K}{\pi}\right)^b$ for rational $b$ and $K$. Find $bK$.

Practice focus

This Probability problem is tagged Expected Value, Continuous Random Variables, Calculus. State the random variables and conditioning information explicitly, then check the result against boundary cases before opening hints or a solution.

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