On a class exhibiting trend change in average failure rate

Abstract

Weak convergence and moment convergence issues are investigated for the New Better than Average Failure Rate (NBAFR) family (introduced by Loh (1984 Loh, W. Y. 1984. A new generalization of the class of NBU distributions. IEEE Transactions on Reliability R-33 :97–113[Crossref], [Web of Science ®] , [Google Scholar])). We explore the validity of these results in the context of a more general ageing class that we introduce. We prove some new properties of this class and derive its interrelationships with other non-monotonic ageing families. Reliability and moment bounds are obtained and an interesting characterization of exponentiality is proved. Special cases of our results lead to new theorems for the NBAFR class. Finally weak convergence and related issues are established for this class.     

Randomized response techniques for complex survey designs

Singh et al. ([13]) pointed out that the Randomized response (RR) technique proposed by Moors ([9]) is not desirable because it fails to protect the confidentiality of the respondents and they provided two alternative strategies free from the above drawback but limited to SRSWOR sampling only. In this paper, generalization of one of the strategies is provided for complex survey designs, wider class of estimators and for quantitative characteristics. Relative efficiency of the modified strategy is tested through empirical investigations. An erratum to this article is available at .     

The status of women among the scheduled tribes in India

The scheduled tribes constitute about 8.2% of the total population in India. Although there is a large volume of anthropological literature describing the characteristics of and differences among the various tribes in India, little inter-disciplinary research has been done to uncover the status of women among the tribal population in India. This paper will analyze the status of women among the scheduled tribes in India. Frequent comparisons will be made to the social and cultural practices of the scheduled tribes, mainstream Hindus, as well as the scheduled caste population. Through this analysis, we will show the distinctiveness of the tribal cultures and the fact that many women from the scheduled tribes face less discrimination than Hindu women and those from scheduled castes.     

Long term demographic effect of a constant stream of immigration when the population is not reproducing itself

The author describes the use of a model to investigate "the age composition of the stationary population resulting from a condition of below replacement fertility and a continuous stream of immigrants, the size of which for any age remain invariant over time.... We have shown that the number dying among [migrants] is the same as the number of them entering over any time interval, and that is precisely how their stationarity is maintained." The geographical focus is on developed countries that are experiencing below-replacement fertility levels. (SUMMARY IN FRE AND SPA)     

BERTRAND COMPETITION WITH ASYMMETRIC MARGINAL COSTS

This article tests the prediction of three discrete asymmetric duopoly price competition games in the laboratory. The games differ from each other in terms of the size of the cost asymmetry that induces a systematic variation in the difference between the firms' marginal costs. While the standard theory requires the low‐cost firm to set a price just equal to the high‐cost firm's marginal cost, which is identical across all three games, and win the entire market, intuition suggests that market price may increase with a decrease in the absolute difference between the two marginal costs. We develop a quantal response equilibrium model to test our competing conjecture. (JEL L11, L12, C91, D43)     

Social Capital Investment and Immigrant Economic Trajectories: A Case Study of Punjabi American Taxi Drivers in New York City

Although the scholarship on social capital and immigrant economic incorporation has sufficiently documented how immigrants mobilize social capital in their search for employment which often leads to the formation of immigrant niches, how social capital is processed after immigrants acquire employment and its significance for the preservation of immigrant employment niches is less well explored. This paper addresses this gap in the literature with a case study of immigrant Punjabi taxi drivers in the New York metropolitan area. In particular, this study shows how a group of immigrant Punjabi taxi drivers mobilized social capital via embeddedness in co‐ethnic social networks and improved their working conditions – a process that must be considered in explanations of the Punjabi niche in the taxi industry for more than two decades. The study has implications for the relationship between social capital and the structure of the workplace or industry where immigrants are incorporated and its subsequent impact on immigrant economic trajectories. Further, this study contributes to the debate on the usefulness of ethnic communities for the adaptation of immigrant groups. Additionally, this research is relevant to the scholarship on the economic adaptation of South Asian (a subset of Asian Americans) immigrants, an understudied immigrant group in the United States.     

Analysis of Type-II hybrid censored competing risks data

Kundu and Gupta [Analysis of hybrid life-tests in presence of competing risks. Metrica. 2007;65:159–170] provided the analysis of Type-I hybrid censored competing risks data, when the lifetime distributions of the competing cause of failures follows exponential distribution. In this paper, we consider the analysis of Type-II hybrid censored competing risks data. It is assumed that latent lifetime distributions of the competing causes of failures follow independent exponential distributions with different scale parameters. It is observed that the maximum likelihood estimators of the unknown parameters do not always exist. We propose the modified estimators of the scale parameters, which coincide with the corresponding maximum likelihood estimators when they exist, and asymptotically they are equivalent. We obtain the exact distribution of the proposed estimators. Using the exact distributions of the proposed estimators, associated confidence intervals are obtained. The asymptotic and bootstrap confidence intervals of the unknown parameters are also provided. Further, Bayesian inference of some unknown parametric functions under a very flexible Beta-Gamma prior is considered. Bayes estimators and associated credible intervals of the unknown parameters are obtained using the Monte Carlo method. Extensive Monte Carlo simulations are performed to see the effectiveness of the proposed estimators and one real data set has been analysed for the illustrative purposes. It is observed that the proposed model and the method work quite well for this data set.     

Classical testing in functional linear models

We extend four tests common in classical regression – Wald, score, likelihood ratio and F tests – to functional linear regression, for testing the null hypothesis, that there is no association between a scalar response and a functional covariate. Using functional principal component analysis, we re-express the functional linear model as a standard linear model, where the effect of the functional covariate can be approximated by a finite linear combination of the functional principal component scores. In this setting, we consider application of the four traditional tests. The proposed testing procedures are investigated theoretically for densely observed functional covariates when the number of principal components diverges. Using the theoretical distribution of the tests under the alternative hypothesis, we develop a procedure for sample size calculation in the context of functional linear regression. The four tests are further compared numerically for both densely and sparsely observed noisy functional data in simulation experiments and using two real data applications.