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What is the expectation of $ X^2$ where $ X$ is distributed normally?

Writer Matthew Martinez
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I know that if $X$ were distributed as a standard normal, then $X^2$ would be distributed as chi-squared, and hence have expectation $1$, but I'm not sure about for a general normal.

Thanks

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1 Answer

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Use the identity $$ E(X^2)=\text{Var}(X)+[E(X)]^2 $$ and you're done.

Since you know that $X\sim N(\mu,\sigma)$, you know the mean and variance of $X$ already, so you know all terms on RHS.

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