On the asymptotic efficiency of the multisample location-scale rank tests and their adjustment for ties

summary:Explicit formulas for the non-centrality parameters of the limiting chi-square distribution of proposed multisample rank based test statistics, aimed at testing the hypothesis of the simultaneous equality of location and scale parameters of underlying populations, are obtained by means of a general assertion concerning the location-scale test statistics. The finite sample behaviour of the proposed tests is discussed and illustrated by simulation estimates of the rejection probabilities. A modification for ties of a class of multisample location and scale test statistics, based on ranks and including the proposed test statistics, is presented. It is shown that under the validity of the null hypothesis these modified test statistics are asymptotically chi-square distributed provided that the score generating functions fulfill the imposed regularity conditions. An essential assumption is that the matrix, appearing in these conditions, is regular. Conditions sufficient for the validity of this assumption are also included

Pranab Kumar Sen: Life and works

In this article, we describe briefly the highlights and various accomplishments in the personal as well as the academic life of Professor Pranab Kumar Sen.Comment: Published in at http://dx.doi.org/10.1214/193940307000000013 the IMS Collections (http://www.imstat.org/publications/imscollections.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

A Conversation with Shoutir Kishore Chatterjee

Shoutir Kishore Chatterjee was born in Ranchi, a small hill station in India, on November 6, 1934. He received his B.Sc. in statistics from the Presidency College, Calcutta, in 1954, and M.Sc. and Ph.D. degrees in statistics from the University of Calcutta in 1956 and 1962, respectively. He was appointed a lecturer in the Department of Statistics, University of Calcutta, in 1960 and was a member of its faculty until his retirement as a professor in 1997. Indeed, from the 1970s he steered the teaching and research activities of the department for the next three decades. Professor Chatterjee was the National Lecturer in Statistics (1985--1986) of the University Grants Commission, India, the President of the Section of Statistics of the Indian Science Congress (1989) and an Emeritus Scientist (1997--2000) of the Council of Scientific and Industrial Research, India. Professor Chatterjee, affectionately known as SKC to his students and admirers, is a truly exceptional person who embodies the spirit of eternal India. He firmly believes that ``fulfillment in man's life does not come from amassing a lot of money, after the threshold of what is required for achieving a decent living is crossed. It does not come even from peer recognition for intellectual achievements. Of course, one has to work and toil a lot before one realizes these facts.''Comment: Published in at http://dx.doi.org/10.1214/088342306000000565 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

The Interaction Effects of Subjective and Structural Factors on Crime Among Formerly Incarcerated Males

The high rate of recidivism in the over 600,000 individuals who return from incarceration each year is an important social problem facing U.S. society and the criminal justice system. Efforts undertaken so far early in the 21st century to address the problem of recidivism in the formerly incarcerated, particularly prison reentry programs, have produced disappointing results at reducing the rate of recidivism. Therefore, there is a need to identify new ways for prison reentry programs to reduce recidivism among individuals recently returned from prison, and social work with its person-in-environment perspective can make an important contribution through conducting research to understand the behavior change process that facilitates termination from crime. Explanations for how individuals terminate from crime are dominated by either a structural perspective or a subjective perspective, but new research has identified a third school of thought, the structural-subjective perspective, that attempts to create an integrated theory from both structural and subjective theories of crime termination. The purpose of the current study was to contribute to the literature on crime termination and the structural-subjective perspective by exploring the nature of the relationship between structural factors, subjective factors, and crime termination in a sample of adolescents with serious criminal backgrounds. Secondary data from the Pathways to Desistance study, a longitudinal study that followed youth convicted of serious crimes in Philadelphia, Pennsylvania and Phoenix, Arizona for seven years, was analyzed using confirmatory factor analysis and structural equation modeling to answer the research questions. The method of multisample analysis within structural equation modeling was also used to examine significant relationships for invariance across race and socioeconomic status. Results found support for an inverse relationship between the latent measure Pro-Social Orientation and Self-Reported Offending. In addition, greater levels of Social Capital were found to increase Pro-Social Orientation, which in turn decreased criminal behavior three-years later. Implications and recommendations for how social workers and prison reentry programs can help to intervene at the structural level and develop social capital in order to increase the likelihood of success among the formerly incarcerated is discussed

Comparison of change-points in multivariate statistical process control using the performance of Lapage-type (nonparametric)

The inability of the Shewhart‟s, the EWMA, and the CUSUM, Hotelling‟s T2 and many other control charts to indicate the time of shift poses great problems in production, Medicine, etc. To overcome the problems the need to identify the period of change (shift) in the process becomes inevitable. The study used Lapage-type Change-point (LCP) to detect the simultaneous shift in both mean and variance. In the study we compare the performance of generalized likelihood ratio change-point (GLRCP) a parametric-base with our proposed method (LCP) at different varying start-ups using real life data. We run the data on Normal, Laplace and Lognormal distributions and also Average Run Length (ARL0) to assess the performance of the methods. Evaluating in-control ARLs (IC-ARLs) for each of the methods at change-point 250 and ARL0 500 indicates the same performance irrespective of the start-up value; LCP and GLR methods have rather a similar performance IC-ARLs at change-point 50 and change-point 100 under the normality assumptions, but under non-normal distributions, LCP has substantially higher IC-ARLs compared to GLRCP at 20. The LCP outperformed the GLRCP when applied to children bronchial pneumonia status. We therefore recommend that new method be used in short-run situations and also when underlying distributions are usually unknown