6 Estimation of scale parameter based on a fixed set of order statistics

Author(s):  
Sanat K. Sarkar ◽  
Wenjin Wang
2011 ◽  
Vol 25 (3) ◽  
pp. 369-391 ◽  
Author(s):  
Peng Zhao

In this article, we study ordering properties of lifetimes of parallel systems with two independent heterogeneous gamma components in terms of the likelihood ratio order and the hazard rate order. LetX1andX2be two independent gamma random variables withXihaving shape parameterr>0 and scale parameter λi,i=1, 2, and letX*1andX*2be another set of independent gamma random variables withX*ihaving shape parameterrand scale parameter λ*i,i=1, 2. Denote byX2:2andX*2:2the corresponding maximum order statistics, respectively. It is proved that, among others, if (λ1, λ2) weakly majorize (λ*1, λ*2), thenX2:2is stochastically greater thanX*2:2in the sense of likelihood ratio order. We also establish, among others, that if 0<r≤1 and (λ1, λ2) isp-larger than (λ*1, λ*2), thenX2:2is stochastically greater thanX*2:2in the sense of hazard rate order. The results derived here strengthen and generalize some of the results known in the literature.


1966 ◽  
Vol 37 (1) ◽  
pp. 152-176 ◽  
Author(s):  
M. B. Wilk ◽  
R. Gnanadesikan ◽  
Elizabeth Lauh

2000 ◽  
Vol 31 (3) ◽  
pp. 165-174
Author(s):  
S. W. Cheng ◽  
C. H. Chou

In this article, we will study the linear estimation of the scale parameter of the generalized Pareto distribution (GPD) which has the probability density function (p.d.f.)$$ f(x)=\left\{\begin{array}{ll} \sigma^{-1}(1-rx/\sigma)^{1/r-1},~~& r\not=0 \\ \sigma^{-1}\exp(-x/\sigma),&r=0. \end{array}\right.$$We first derive the expected value, variances and covariances of the order statistics from the GPD. Then proceed to find the best linear unbiased estimates of the scale parameter $\sigma$ based on a few order statistics selected from a complete sample or a type-II censored sample. Results of some chosen cases were tabulated.


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