A NOTE ON A MULTIVARIATE GENERALIZATION OF THE KRUSKAL-WALLIS TEST

Marketers are often interested in testing whether the mean vectors of multivariate distributions are equal. The test usually applied, one-way MANOVA, assumes the distributions are multinormal. Unfortunately, this assumption is not supported in many studies. As an alternative, a nonparametric multivariate one-way analysis of variance procedure is presented.     

THE BIAS OF COST CONTROL CHARTS TOWARD TYPE II ERRORS

Application of control charts has significantly improved process control by explicitly recognizing uncontrollable variation in the process. A dangerous misapplication of the technique involves the use of control charts with data produced by accounting systems. This paper points out the weaknesses inherent in using aggregated accounting data for inferences about cost control.     

ALTERNATIVES TO EXPECTANCY THEORIES OF WORK MOTIVATION

A number of criticisms of expectancy theory as an explanation of work effort have been raised in recent months. These criticisms are basic enough and based on sound enough evidence to warrant consideration of possible alternate frameworks for the study of work effort. Promising alternatives are: (1) Detuned Cognitive Models; (2) Acognitive Models; and (3) Combined Cognitive and Acognitive Models.     

Was there compression of disability for older Americans from 1992 to 2003?

Medical advances and the growth of the elderly population have focused interest on trends in the health of the elderly. Three theories have been advanced to describe these trends: compression of morbidity, expansion of morbidity, and dynamic equilibrium. We applied multistate life table methods to the Medicare Current Beneficiary Survey to estimate active and disabled life expectancy from 1992 to 2003, defining disability as having difficulty with instrumental activities of daily living or activities of daily living. We found increases in active life expectancy past age 65 and decreases in life expectancy with severe disability. These trends are consistent with elements of both the theory of compression of morbidity and the theory of dynamic equilibrium.     

Using age and spatial flow structures in the indirect estimation of migration streams

This article outlines a formal model-based approach for inferring interregional age-specific migration streams in settings where such data are incomplete, inadequate, or unavailable. The estimation approach relies heavily on log-linear models, using them to impose some of the regularities exhibited by past age and spatial structures or to combine and borrow information drawn from other sources. The approach is illustrated using data from the 1990 and 2000 U.S. and Mexico censuses.     

Differential equation models for statistical functions

Differential equations have been used in statistics to define functions such as probability densities. But the idea of using differential equation formulations of stochastic models has a much wider scope. The author gives several examples, including simultaneous estimation of a regression model and residual density, monotone smoothing, specification of a link function, differential equation models of data, and smoothing over complicated multidimensional domains. This paper aims to stimulate interest in this approach to functional estimation problems, rather than provide carefully worked out methods.     

Bootstrap tests: how many bootstraps?

In practice, bootstrap tests must use a finite number of bootstrap samples. This means that the outcome of the test will depend on the sequence of random numbers used to generate the bootstrap samples, and it necessarily results in some loss of power. We examine the extent of this power loss and propose a simple pretest procedure for choosing the number of bootstrap samples so as to minimize experimental randomness. Simulation experiments suggest that this procedure will work very well in practice.     

Residential preferences and population distribution

Public opinion research has revealed decided preferences for living in rural areas and small towns, and proponents of population deconcentration have interpreted this as support for their policies. This study, based on a national sample, yielded similar results, but when we introduced the additional possibility of a preference for proximity to a larger city, then the rural areas preferred were found, for most respondents, to be those within the commuting range of a metropolitan central city. Although persons wishing to live near large cities were found to be looking for the same qualities of living sought by those who prefer a more remote location, these findings are not, in general, consistent with the argument that public preferences support strategies of population dispersal into nonmetropolitan areas. Instead they indicate that most of those who wish to live in a different location favor the peripheral metropolitan ring areas that have, in fact, been growing rapidly by in-migration.