Scale estimators for symmetric stable distributions

This paper reports on a simulation comparison of scale estimators for symmetric stable distributions in terms of their ability to identify the population with the greater scale. The modified geometric mean is found to be superior to the sample standard deviation and the Fama-Roll estimator for the larger values of the characteristic exponent, while the Fama-Roll estimator is judged superior for the smaller values. Further, this study sheds some light on the question of the appropriate sample size for discriminating risk measurement in investment analysis when the samples are taken from symmetric stable distributions.     

An extended class of permutation techniques for matched pairs

A class of matched-pairs permutation techniques based on distances between each pair of observed signed values is considered. Although many commonly-used inference techniques for matched pairs are members of this class, some of the more appealing inference techniques among this class have received very little attention. Two new simple rank tests of this class jointly possess both intuitive properties and location-alternative power characteristics which appear more appealing than the corresponding characteristics of either the sign test or the Wllcoxon signed-ranks test. In particular, power comparisons based on slmula-tions indicate that these new rank tests are jointly as good or even vastly superior to the sign test or the Wilcoxon signed-ranks test for location alternatives involving five symmetric distributions. The five distributions selected for these com-parisons include the Laplace, logistic, normal, uniform and a U-shaped distribution     

Non-random shuffling strategies in blackjack

Numerous playing and betting strategies for the game of twenty-one have been computed assuming the deck or decks are randomly shuffled. In practice, dealers do not spend the time necessary (it takes too long) to completely randomly shuffle the decks used. Hence, there is information not only from the current round of play, but potentially from the previous round of play. We present a model for a non-random shuffle and assert ways in which this information can be used. Rules are derived using a normal approximation which updates the current strategies utilizing information from a non-random shuffle.     

Psychological distress and mortality: are women more vulnerable?

Does psychological distress increase mortality risk? If it does, are women more vulnerable than men to the effect of distress on mortality? Drawing from cumulative disadvantage theory, these questions are addressed with data from a 20-year follow-up of a national sample of adults ages 25-74. Event history analyses were performed to examine mortality from general and specific causes for men and women. Findings reveal that the effect of psychological distress on all-cause mortality was nonlinear for men. Moderate amounts of distress were associated with lower mortality risk, but high levels of distress raised men's mortality risk. Moreover the curvilinear relationship between distress and mortality varied by cause of death for men and women. Men with high levels of psychological distress were more vulnerable to ischemic heart disease mortality. Women with high levels of distress were more vulnerable to cancer mortality.     

Uncertainty and forecasting local health professional shortages

We used a utilization-based scenario-forecasting model toassess the evidence for current and future imbalances between health professional supply and demand in Memphis-Shelby County, Tennessee. The scenario-forecasting model, based on qualitativeinformation collected from local health industry leaders, was shaped and limited by the types of current local area data available. This paper discusses methods that may prove useful to applied demographers making forecasts, given uncertain system change and poor data.     

Growing Diversity among America's Children and Youth: Spatial and Temporal Dimensions

This study documents the changing racial and ethnic mix of America's children. Specifically, we focus on the unusually rapid shifts in the composition and changing spatial distribution of America's young people between 2000 and 2008. Minorities grew to 43 percent of all children and youth, up from 38.5 percent only eight years earlier. In 1990, this figure stood at 33 percent. Among 0–4‐year‐olds, 47 percent of all children were minority in 2008. Changes in racial and ethnic composition are driven by two powerful demographic forces. The first is the rapid increase since 2000 in the number of minority children—with Hispanics accounting for 80 percent of the growth. The second is the absolute decline in the number of non‐Hispanic white children and youth. The growth of minority children and racial diversity is distributed unevenly over geographical space. Over 500 (or roughly 1 in 6) counties now have majority‐minority youth populations. Broad geographic areas of America nevertheless remain mono‐racial, where only small shares of minorities live.     

Commentary on “Analysis of Choice Expectations in Incomplete Scenarios”

Journal of Risk and Uncertainty -