Abstract
Let n≥ 3 and let X 1,...,X n be positive i.i.d. random variables whose common distribution function f has a continuous p.d.f. Using earlier work of the present authors and a method due to Anosov for solving certain integro-functional equations, it is shown that the independence of the sample mean and the sample coefficient of variation is equivalent to that f is a gamma function. While the proof is of methodological interest, this conclusion can also be arrived at without any assumptions by appealing to the Laplace-Stieltjes transform, as in the Concluding Romark (Section 3).
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Hwang, TY., Hu, CY. On a Characterization of the Gamma Distribution: The Independence of the Sample Mean and the Sample Coefficient of Variation. Annals of the Institute of Statistical Mathematics 51, 749–753 (1999). https://doi.org/10.1023/A:1004091415740
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DOI: https://doi.org/10.1023/A:1004091415740