Modified inference about the mean of the exponential distribution using moving extreme ranked set sampling

The maximum likelihood estimator (MLE) and the likelihood ratio test (LRT) will be considered for making inference about the scale parameter of the exponential distribution in case of moving extreme ranked set sampling (MERSS). The MLE and LRT can not be written in closed form. Therefore, a modification of the MLE using the technique suggested by Maharota and Nanda (Biometrika 61:601–606, 1974) will be considered and this modified estimator will be used to modify the LRT to get a test in closed form for testing a simple hypothesis against one sided alternatives. The same idea will be used to modify the most powerful test (MPT) for testing a simple hypothesis versus a simple hypothesis to get a test in closed form for testing a simple hypothesis against one sided alternatives. Then it appears that the modified estimator is a good competitor of the MLE and the modified tests are good competitors of the LRT using MERSS and simple random sampling (SRS).     

Life satisfaction and family structure among adolescents in Hong Kong

Relationships between family structure and perceived life satisfaction in overall life and five domains of the Brief Multidimensional Students’ Life Satisfaction Scale, family life, friendships, school experience, myself, and where I live were examined among 4,502 Chinese adolescent secondary school students in Hong Kong. Bivariate analyses showed that economic status was not a significant risk factor, but gender, level of study, and migrant status had to be controlled to examine the life satisfaction-family structure relations. Logistic regression analyses found that in overall life, with adolescents living with two parents as standard for comparisons, adolescents living with mother had similar life satisfaction, but those living with father only, and those with no parents, or single parent with other adults had very much higher risk of life dissatisfaction. Specifically, the risks associated with the adverse family structures were most excessive in the domain of ‘family life’.     

出生人口性别比与和谐社会建设:一个定性和定量分析

20世纪80年代中期以来,中国的出生性别比持续攀升,出生人口性别结构严重失衡。运用定性和定量相结合的研究方法,探讨出生性别比失衡的潜在因素和制度因素。分析结果表明,农村地区出生性别比的失衡与儿子预期的经济价值和文化功用相关。最后提出具有针对性的缓解出生性别比失衡的建议。     

和谐社会构建中的不和谐人口因素探析——基于广东省出生性别比偏高问题的研究

人口性别比协调是一重要的社会"稳定器"和"平衡未",而出生性别比是人口性别比的先导.广东省在构建和谐社会进程中所面临的不和谐人口要素之一便是出生性别比偏高.通过从孩次、城乡、区域以及人口流迁等方面进行剖析,广东省出生人口性别比在上述几个方面均出现了不同程度的失衡.通过"利离"发现,广东省出生人口性别比的总体偏高主要还是由于粤北和粤西等不发达地区农村户籍育龄妇女的超高出生性别比拉动所致,主要应从现念、领导、管理和法制等面标本兼治、综合治理.     

A lost family-planning regime in eighteenth-century Ceylon

Based on Dutch colonial registers (thombos), this paper reconstructs fertility for two districts in Ceylon, 1756–68. It overcomes challenges in data quality by establishing the outer bounds of plausible estimates in a series of scenarios. Among these, total fertility rates (TFRs) averaged 5.5 in one district, but only 2.7 in the other. These figures exclude the victims of infanticide, a custom noted in European travelogues between about 1660 and 1820. Sex ratios among children differed depending on the number of older siblings, and overall, 27?per cent of girls are missing in one district and 57?per cent in the other. There was little significant variation either in the TFR or the sex ratio by socio-economic status, suggesting that poverty was not a key factor in motivating infanticides. Instead, we argue that at least parts of Ceylon had a forward-looking culture of family planning in the eighteenth century, which was lost in subsequent decades.     

基于市盈率、预期和供求关系的股价行为动态分析模型

针对现有股票价格模型的局限性,提出一个基于市盈率、预期及供求关系的股票价格行为动态分析模型。本模型考察市盈率、预期对股票市场供求关系的影响,探讨股票价格行为与投资者对公司未来每股收益的预期之间的关系,分析现行市盈率及动态市盈率与投资者普遍认可的合理市盈率之间的偏差对上述关系的影响,得出股票价格是在投资者对公司未来每股收益不断预期和矫正,以及对现行市盈率、动态市盈率与他们认可的合理市盈率之间偏差的不断判断和调整的基础上和由此导致的供求力量的作用下,围绕市场普遍认可的合理市盈率而上下波动的结论。     

Generalized Kerridge’s inaccuracy measure for conditionally specified models

Recently, conditional Renyi’s divergence of order α and Kerridge’s inaccuracy measures are studied by Navarro et al. (2014 Navarro, J., Sunoj, S.M., Linu, M.N. (2014). Characterizations of bivariate models using some dynamic conditional information divergence measures. Commun. Stat. Theory Methods 43:1939–1948.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). In the present article, a generalized dynamic conditional Kerridge’s inaccuracy measure is introduced, which can be represented as the sum of conditional Renyi’s divergence and Renyi’s entropy. Some useful bounds are obtained using the concept of likelihood ratio order. The results are extended to weighted distributions. Sufficient conditions are obtained for the monotonicity of the proposed measure. Characterizations for bivariate exponential conditional distribution are presented based on the proposed measure.     

On confidence intervals for the mean past lifetime function under random censorship

The mean past lifetime (MPL) function (also known as the expected inactivity time function) is of interest in many fields such as reliability theory and survival analysis, actuarial studies and forensic science. For estimation of the MPL function some procedures have been proposed in the literature. In this paper, we give a central limit theorem result for the estimator of MPL function based on a right-censored random sample from an unknown distribution. The limiting distribution is used to construct normal approximation-based confidence interval for MPL. Furthermore, we use the empirical likelihood ratio procedure to obtain confidence interval for the MPL function. These two intervals are compared with each other through simulation study in terms of coverage probability. Finally, a couple of numerical example illustrating the theory is also given.     

Generalized simultaneous confidence regions for regression coefficients and their ratios

This study constructs a simultaneous confidence region for two combinations of coefficients of linear models and their ratios based on the concept of generalized pivotal quantities. Many biological studies, such as those on genetics, assessment of drug effectiveness, and health economics, are interested in a comparison of several dose groups with a placebo group and the group ratios. The Bonferroni correction and the plug-in method based on the multivariate-t distribution have been proposed for the simultaneous region estimation. However, the two methods are asymptotic procedures, and their performance in finite sample sizes has not been thoroughly investigated. Based on the concept of generalized pivotal quantity, we propose a Bonferroni correction procedure and a generalized variable (GV) procedure to construct the simultaneous confidence regions. To address a genetic concern of the dominance ratio, we conduct a simulation study to empirically investigate the probability coverage and expected length of the methods for various combinations of sample sizes and values of the dominance ratio. The simulation results demonstrate that the simultaneous confidence region based on the GV procedure provides sufficient coverage probability and reasonable expected length. Thus, it can be recommended in practice. Numerical examples using published data sets illustrate the proposed methods.     

On analysis of binary response data in longitudinal factorial studies

Binary data are commonly used as responses to assess the effects of independent variables in longitudinal factorial studies. Such effects can be assessed in terms of the rate difference (RD), the odds ratio (OR), or the rate ratio (RR). Traditionally, the logistic regression seems always a recommended method with statistical comparisons made in terms of the OR. Statistical inference in terms of the RD and RR can then be derived using the delta method. However, this approach is hard to realize when repeated measures occur. To obtain statistical inference in longitudinal factorial studies, the current article shows that the mixed-effects model for repeated measures, the logistic regression for repeated measures, the log-transformed regression for repeated measures, and the rank-based methods are all valid methods that lead to inference in terms of the RD, OR, and RR, respectively. Asymptotic linear relationships between the estimators of the regression coefficients of these models are derived when the weight (working covariance) matrix is an identity matrix. Conditions for the Wald-type tests to be asymptotically equivalent in these models are provided and powers were compared using simulation studies. A phase III clinical trial is used to illustrate the investigated methods with corresponding SAS® code supplied.