Trivial Question on Gamma Distribution Function

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SUMMARY

The discussion focuses on the properties of the Gamma Distribution Function, specifically how adding a constant to a random variable affects its distribution. When a random variable X follows a standard Gamma Distribution with parameter α, the addition of a constant k results in a new random variable Y that follows a generalized gamma distribution. The probability density function (pdf) for Y is defined as P_Y(x)=\frac{1}{\Gamma(\alpha)\lambda^\alpha}(x-a)^{\alpha-1}e^{-(x-a)/\lambda}, indicating that Y+k follows a Gamma distribution with parameters α, a+k, and λ.

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If a random variable X follows Gamma Distribution Function with parameters K and thita, what does (X+k) follow? if K is a constant.
I think, since adding the constant is just like shifting the origin, the nature of the curve remain unchanged. But what about its parameter?
Thanks.
 
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Let X be the standard gamma distribution with parameter \alpha. Then this has pdf

p_X(x)=\frac{1}{\Gamma (\alpha)}x^{\alpha-1} e^{-x}

for x>0. Then we define the generalized gamma distribution as Y=a+\lambda X. This has pdf

P_Y(x)=\frac{1}{\Gamma(\alpha)\lambda^\alpha}(x-a)^{\alpha-1}e^{-(x-a)/\lambda}

if x>a. This is the \Gamma(\alpha,a,\lambda)-distribution. The standard gamma is \Gamma(\alpha,0,1). So to answer your question:

if Y\sim \Gamma(\alpha,a,\lambda), then Y+k\sim \Gamma(\alpha,a+k,\lambda).
 
Thank you for your kind help.
 

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