Testing for a separation between two normal distributions

Three tests are proposed for testing for a specified degree of overlap between two normal distributions, The hypotheses considered are an extension of the Behrens-Fisher problem, A simulation study of the performance of the tests is presented.     

Alternative beta estimation for the market model using partially adaptive techniques

The leptokurtosls of many security market return distributions can contaminate ordinary least squares estimates of the β coefficient of the market model. Partially adaptive estimation techniques accommodate the possibility of fat tailed distributions. this methodology limits the influence of extremely large residuals and yields estimates which are both statistically and practically different from ordinary least squares.     

The probability integral for a bivariate generalization of the non-central t

An expression for the probability integral of a bivariate generalization of the non-central t distribution is derived. This expression is then used to construct tables for various combinations of parameter values     

On confidence regions for the mean of a multivariate time series

We consider the problem of setting up a confidence region for the mean of amultivariate timeseries ont he basis of a part-realisation of that series.A procedure for setting up a confidence interval for the mean of a univariate time series Is implicitin Jones(1976).We present an analogous procedure for setting up a confidence region for the mean of a multivariatet ime series.This procedure is base donastatistic which is an analogue of Hotelling'sT'.Our results are applied to a comparison of climate means obtained from experiments with a General Circulation Model of the earth's atmosphere.     

On population‐based measures of agreement for binary classifications

The authors describe a model‐based kappa statistic for binary classifications which is interpretable in the same manner as Scott's pi and Cohen's kappa, yet does not suffer from the same flaws. They compare this statistic with the data‐driven and population‐based forms of Scott's pi in a population‐based setting where many raters and subjects are involved, and inference regarding the underlying diagnostic procedure is of interest. The authors show that Cohen's kappa and Scott's pi seriously underestimate agreement between experts classifying subjects for a rare disease; in contrast, the new statistic is robust to changes in prevalence. The performance of the three statistics is illustrated with simulations and prostate cancer data.     

College student binge drinking and the "prevention paradox": implications for prevention and harm reduction

Considerable attention has been paid to heavy episodic or "binge" drinking among college youth in the United States. Despite widespread use, the binge measure is perceived by some as a low intervention threshold. We use data from the Harvard School of Public Health College Alcohol Study (n = 49,163) to describe patterns of consumption and harms along a continuum including the binge measure to demonstrate the validity of the binge threshold and prevention paradox in college. While the heaviest drinkers are at greatest risk for harm, they are relatively few and generate proportionately small amounts of all drinking-harms. The risk of harms is not zero among lower level drinkers in college. Because they are numerous, they account for the majority of harms. This paradoxical pattern suggests we moderate consumption among the majority using environmental approaches, the efficacy of which are described using case study data from a national prevention demonstration. Implications for prevention policy, programming, and media advocacy are discussed.     

Hospitalists: who they are and what they do

The hospitalist movement is spreading like wildfire. Find out the latest statistics on hospitalists.     

OUT OF UTOPIA:

An important segment of writings on postindustrialization is distinctly utopian in stressing the greater mastery and control made possible by recent innovations in information technology. The utopian theme underscores the technical outcomes of innovations and highlights their benefits for ameliorating social problems. By contrast, our work suggests that many of the social problems in contemporary society are a consequence of recent innovations in information technology. We argue that postindustrial theorists are correct in stressing mastery over certain technical problems but incorrect in slighting the destabilizing effect innovations have on organizations and the markets in which these organizations participate. These destabilizing effects complicate organizational strategies by increasing market risk and uncertainty. Since most organizations are risk aversive, social problems are created as organizations externalize their costs and pass along risk to other, more dependent actors. Illustrations from two institutions, politics and the economy, indicate that many postindustrial innovations are associated with heightened competition as well as greater risk and uncertainty across the institutional order. We conclude that postindustrial technology introduces no net gain in man aging the complexities of the social world. Risk and control are both integral to technological innovation and constitute the paradox of postindustrialization.