A one-sided test for testino homogeneity of scale parameters against simple ordered alternative

Abstract

In an earlier paper the authors (1997) extended the results of Hayter (1990) to the two parameter exponential probability model. This paper addressee the extention to the scale parameter case under location-scale probability model. Consider k (k≧3) treatments or competing firms such that an observation from with treatment or firm follows a distribution with cumulative distribution function (cdf) Fi(x)=F[(x-μi)/Qi], where F(·) is any absolutely continuous cdf, i=1,…,k. We propose a test to test the null hypothesis H0:θ1=…=θk against the simple ordered alternative H1:θ1≦…≦θk, with at least one strict inequality, using the data Xi,j, i=1,…k; j=1,…,n1. Two methods to compute the critical points of the proposed test have been demonstrated by talking k two parameter exponential distributions. The test procedure also allows us to construct simultaneous one sided confidence intervals (SOCIs) for the ordered pairwise ratios θj/θi, 1≦i<j≦k. Statistical simulation revealed that: 9i) actual sizes of the critical points are almost conservative and (ii) power of the proposed test relative to some existing tests is higher.