Communications of the
Korean Mathematical Society
CKMS

ISSN(Print) 1225-1763 ISSN(Online) 2234-3024

Article

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Commun. Korean Math. Soc. 2003; 18(1): 127-131

Printed March 1, 2003

Copyright © The Korean Mathematical Society.

Characterizations of the pareto distribution by conditional expectations of record values

Min-Young Lee

Dankook University

Abstract

Let $ X_1 , X_2 , \cdots $ be a sequence of independent and identically distributed random variables with continuous cumulative distribution function $ F(x).$ $ X_j $ is an upper record value of this sequence if $ X_j > \max\{ X_1 , X_2 , \cdots , X_{j-1} \}.$ We define $ u(n) = \min \{j \vert j$ $ > u(n-1), X_j > X_{u(n-1)}, n \geq 2 \} $ with $ u(1) = 1.$ Then $ F(x)$ $=1-x^{\theta},\, \, x>1, \,\, \theta<-1$ if and only if $(\theta+1)E[X_{u(n+1)}|X_{u(m)}$ $=y] = \theta E[X_{u(n)}| X_{u(m)}=y],$ $(\theta+1)^2 E[X_{u(n+2)}|X_{u(m)}=y] = \theta^2 E[X_{u(n)}| X_{u(m)}=y]\,, $ or $ (\theta+1)^3 E[X_{u(n+3)}|X_{u(m)}=y] = \theta^3 E[X_{u(n)}| X_{u(m)}=y],$\,\, $n \ge m+1 .$

Keywords: absolutely continuous distribution, characterization, con -ditional expectation, pareto distribution, record value

MSC numbers: 62E15, 62E10