On estimating the reliability after sequentially estimating the mean: The exponential case

Sequential estimation problems for the mean parameter of an exponential distribution has received much attention over the years. Purely sequential and accelerated sequential estimators and their asymptotic second-order characteristics have been laid out in the existing literature, both for minimum risk point as well as bounded length confidence interval estimation of the mean parameter. Having obtained a data set from such sequentially designed experiments, the paper investigates estimation problems for the associatedreliability function. Second-order approximations are provided for the bias and mean squared error of the proposed estimator of the reliability function, first under a general setup. An ad hoc bias-corrected version is also introduced. Then, the proposed estimator is investigated further under some specific sequential sampling strategies, already available in the literature. In the end, simulation results are presented for comparing the proposed estimators of the reliability function for moderate sample sizes and various sequential sampling strategies.     

Robust political economy

This paper introduces the idea of “robust political economy.” In the context of political economic systems, “robustness” refers to a political economic arrangement's ability to produce social welfare-enhancing outcomes in the face of deviations from ideal assumptions about individuals' motivations and information. Since standard assumptions about complete and perfect information, instantaneous market adjustment, perfect agent rationality, political actor benevolence, etc., rarely, if ever actually hold, a realistic picture and accurate assessment of the desirability of alternative political economic systems requires an analysis of alternative systems' robustness. The Mises-Hayek critique of socialism forms the foundation for investigations of robustness that relax ideal informational assumptions. The Buchanan-Tullock public choice approach complements this foundation in forming the basis for investigations of robustness that relax ideal motivational assumptions. JEL Code B53, P16, P26     

OWNERSHIP VERSUS TIMING OF THE GAME

This study examines the impact of timing of the game on the welfare gains of privatisation in the presence of strategic trade policy. We argue that only if the public enterprise acts as a Cournot player will it generate an additional distortion that could outweigh the distortion caused by the oligopolistic behaviour of private firms. But with a first-mover advantage it can serve as an effective regulatory device comparable with a production subsidy. We further show that, in the presence of strategic trade policy, Cournot assumptions are inconsistent with the firms' preferences over the timing of the game. As public Stackelberg leadership is a subgame Nash equilibrium of the extended game with endogenous order of moves, we conclude that it is the timing of the game rather than firms' ownership structure which is responsible for the inefficiency of an international mixed market found by earlier studies.     

DOES WORKSHARING WORK? SOME EMPIRICAL EVIDENCE FROM THE IAB‐ESTABLISHMENT PANEL

Recent policy debate in Europe suggests that a shorter workweek will lead to more jobs (worksharing). We derive and estimate a model where the firm employs two types of workers, some working overtime, the rest standard hours. Worksharing is not always a prediction of the theory. Using German establishment‐level panel data (the IAB‐ESTABLISHMENT panel), 1993–1999, we find no evidence of pro‐worksharing effects except in small plants in the East German non‐service sector. There is evidence that a cut in standard hours lowers the proportion of overtime workers in a plant, as predicted by the theory, and increases the proportion of standard‐time plants.     

A note on the extension of tables for the Friedman statistic

Abstract  The tables for the Friedman rank-test arc extended using a sampling method. A table is given for the traditional significance levels .01, .025, .05 and .10 for number of blocks equal to 7 and 8 and for treatments of size 6 and 7. A brief discussion of available tables is also included along with an example of an application.     

Exceptional Convergence of the Sample Variance

The case is investigated when Hoeffding's one sample U–statistic theorem for the sample variance S² is not applicable. It is shown that this occurs only when the parent distribution is the two–point distribution with jumps of equal magnitude. For this exceptional case the standardised S² is shown to converge in distribution to (1 – V )√2, where V has chi–square distribution with one degree of freedom.     

Exact finite sample properties of double k-class estimators in simultaneous equations

In our earlier paper [Srivastava, Agnihotri and Dwivedi (1980)] the dominance of double k-class over k-class with respect to exact mean squared error matrix criteria is established. It is observed that given a member of k-class, one can pick up a member of double k-class that will provide an improved estimator of the coefficients. This result prompted us to study the exact finite sample properties of the double k-class estimator. For this, we have considered a structural equation containing two endogenous variables and have investigated the properties of double k-class estimators of the coefficients of explanatory endogenous variables assuming characterizing scalars to be non-stochastic.     

A probability inequality for ranges and its application to maximum range test procedures

Summary It is proved that for any fixed argument the sequence (P _k) of the distribution functions of the ranges ofk i.i.d. univariate random variables is log-concave if the random variables have a log-concave density. If the support of the distribution is an infinite interval and the density is monotonous then the theorem holds also with “log-convex” instead of “log-concave”. The resulting inequalities can be used by a quick algorithm for closed maximum range test procedures for all pairwise comparisons (Royen 1988, 1989a, 1989b). Under the above assumptions the application of this algorithm can be extended e.g. to pairwise comparisons of variances.