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Moment Generating Function of the Gamma Distribution

题目

Let XGamma(α,λ)X \sim \text{Gamma}(\alpha, \lambda) with PDF f(x)=λαΓ(α)xα1eλxf(x) = \frac{\lambda^\alpha}{\Gamma(\alpha)} x^{\alpha-1} e^{-\lambda x} for x>0x > 0. Derive the moment generating function MX(t)=E[etX]M_X(t) = E[e^{tX}] for t<λt < \lambda. Then use MX(t)M_X(t) to compute E[X]E[X] and Var(X)\text{Var}(X).

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你的答案

MGF

E[X]

Var(X)