Asymptotic non-null distribution of a test of equality of exponential populations

In this paper further asymptotic expansions of the non-null distribution of the likelihood ratio criterion for testing the equality of several one parameter exponential distributions are obtained when the alternatives are close to the hypothesis. These expansions are obtained for the first time in terms of beta distributions.     

Geeta distribution and its properties

A new discrete distribution defined over all the positive integers and with the name of Geeta distribution is described. It is L-shaped like the logarithmic series distribution, Yule distribution and the discrete Pareto distribution but is far more versatile than them as it has two parameters. It belongs to the classes of location parameter distributions, modified power series distributions, Lagrange series distributions and exponential distributions. Its mean fi, variance a2 and two recurrence formulae for higher central moments are obtained. Convolution theorem and variations in the model with changes in the parameters have been considered. ML estimators, MVU estimators and estimators based of mean and variance and on mean and first frequency have been derived.     

Features of the demography of Palestine

The objections which Dr Bromberger raises against official vital statistics in Palestine are considered by the author in this paper, and Dr Bromberger's methods of estimation are carefully examined. While defects in the statement of ages and some under-registration of Moslem deaths are admitted, the conclusion is reached that there is no inherent inconsistency in the published figures, and that any errors would not affect the differential rates of growth of the Arab and Jewish populations.     

Comparing MCDA Aggregation Methods in Constructing Composite Indicators Using the Shannon-Spearman Measure

Composite indicators have been increasingly recognized as a useful tool for performance monitoring, benchmarking comparisons and public communication in a wide range of fields. The usefulness of a composite indicator depends heavily on the underlying data aggregation scheme where multiple criteria decision analysis (MCDA) is commonly used. A problem in this application is the determination of an appropriate MCDA aggregation method. Of the many criteria for comparing MCDA methods, the Shannon-Spearman measure (SSM) is one that compares alternative MCDA aggregation methods in constructing composite indicators based on the information loss concept. This paper assesses the effectiveness of the SSM using Monte Carlo approach-based uncertain analysis and variance-based sensitivity analysis techniques. It is found that most of the variation in the SSM arises from the uncertainty in choosing an aggregation method. Therefore, the SSM can be considered as an effective measure for comparing MCDA aggregation methods in constructing composite indicators. We also use the SSM to evaluate five MCDA aggregation methods in constructing composite indicators and present the findings.     

EFFECTS OF EXPOSURE ON PREVALENCE AND CUMULATIVE RELATIVE RISK: DIRECT AND INDIRECT EFFECTS IN A RECURSIVE HAZARD MODEL

This paper outlines decomposition methods for assessing how exposure affects prevalence and cumulative relative risk. Let     x     denote a vector of exogenous covariates and suppose that a single dimension of time   t   governs two event processes     T ₁  and   T ₂.    If the occurrence of the event     T ₁    determines entry into the risk of the event     T ₂,    then subgroup variation in     T ₁    will affect the prevalence     T ₂,    even if subgroups in the population are otherwise identical. Although researchers often acknowledge this phenomenon, the literature has not provided procedures to assess the magnitude of an exposure effect of     T ₁    on the prevalence of     T ₂.    We derive decompositions that assess how variation in exposure generated by direct and indirect effects of the covariates     x     affect measures of absolute and relative prevalence of     T ₂.    We employ a parametric but highly flexible specification for baseline hazard for the     T ₁  and   T ₂    processes and use the resulting parametric proportional hazard model to illustrate the direct and indirect effects of family structure when     T ₁    is age at first sexual intercourse and     T ₂    is age at a premarital first birth for data on a cohort of non-hispanic white U.S. women.     

Evaluation of two school‐based HIV prevention interventions in the border city of Tijuana,Mexico

This research project examined the individual and combined effectiveness of an HIV prevention workshop and a free condom distribution program in four high schools in Tijuana, Mexico. Adolescents (N = 320) completed baseline measures on sexual practices and theoretical correlates and participated in a two‐part study. In Study I, students were randomly assigned to an HIV prevention workshop or a control condition, with a 3‐month follow‐up assessment. Results indicate three significant workshop benefits regarding HIV transmission by altering sexual initiation, access to condoms, and traditional beliefs regarding condoms. In Study 2, we set up a condom distribution program at two of the participating schools, and students completed a 6‐month follow‐up assessment. Results indicate that exposure to the workshop followed by access to the condom distribution program yielded two beneficial results for reducing HIV transmission: moderating sexual initiation and increasing condom acquisition. Access to the condom distribution program alone had no effects on behavioral and psy‐chosocial correlates of HFV transmission. We discuss implications of these results.     

Projektmanagement mit virtuellen Teams?

Globalisation and internationalisation of organisations as well as fast-paced development of modern electronic communication technologies require and support the implementation of globally distributed project teams. Members are working together in different locations and in different time zones. These facts have an impact on project work. This article tries to critically reflect the work of virtual project teams and it tries to answer the question, if we can speak about teamwork under such circumstances.     

Sex,Arts and Verbal Abilities: Three Further Indicators of How American Life is not Improving

Despite clear evidence that Americans’ economic standard of living has improved over the last half-century in terms of income, ownership of technology and housing among other indicators, there is scant evidence from non-economic quality-of-life (QOL) indicators of improved life quality to parallel these economic gains. The present article adds to this list in showing little if any progress in three QOL indicators (the first two about time and activity) that have received less or no attention in the social indicators literature, namely (1) frequency of the highly enjoyable activity of sex, (2) participation in various serious arts activities and (3) scores of verbal ability. The data on sexual activity and verbal ability come from the 1974–2008 General Social Surveys (GSS) from the University of Chicago, and for the arts from the 2008 Survey of Public Participation in the Arts (SPPA) conducted by the US Census Bureau for the National Endowment for the Arts since 1982. All three surveys interviewed nationally representative samples, with over 70% response rates and sample sizes of more than 15,000 adults. The GSS data on sexual frequency show no significant increase in estimated frequency of sex since 1989, despite its strong appeal and the availability of new societal conveniences. This held both before and after adjustment for the age, marital status and education in the population; contrary to expectation, working long hours was associated with increased sex both before and after adjustment for these other demographic predictors. The SPPA trend data on arts participation actually showed a decline in participation, especially after adjustment for its major predictor of years of education; again no decreased participation was found among those working long hours. While scores on verbal ability in the GSS have stayed rather steady since 1974, they have decreased after MCA adjustment for the increased college education in more recent years, as documented by Nie et al. (2009). Thus, contrary to expectations, increases in public education have not been accompanied by improvements on these three indicators.     

The eigenstructure of block-structured correlation matrices and its implications for principal component analysis

Block-structured correlation matrices are correlation matrices in which the p variables are subdivided into homogeneous groups, with equal correlations for variables within each group, and equal correlations between any given pair of variables from different groups. Block-structured correlation matrices arise as approximations for certain data sets’ true correlation matrices. A block structure in a correlation matrix entails a certain number of properties regarding its eigendecomposition and, therefore, a principal component analysis of the underlying data. This paper explores these properties, both from an algebraic and a geometric perspective, and discusses their robustness. Suggestions are also made regarding the choice of variables to be subjected to a principal component analysis, when in the presence of (approximately) block-structured variables.