Survey of Voluntary Recreation Workers in New South Wales

Two surveys were conducted of volunteers working for recreation organizations in four New South Wales regions. The results highlight the dependence of these organizations on volunteers. Volunteers were found to be heavily engaged in instructing and organizing recreation activities. Few have any specific training for the role although further training is frequently considered desirable by respondents. Many respondents indicated that the government could assist voluntary work by providing— ? training at the local level, ? general financial assistance, and ? subsidies for equipment and facilities. Generally, responses indicate that the government should play a supportive rather than controlling role in recreation.     

Chemical Accidents in the United States, 1990–1996

Objective. Much of the empirical work on environmental justice centers on the geographic distribution of potential chronic health risks (e.g., planned toxic releases or treatment storage and disposal facilities). Far less attention has been devoted to the geographic distribution of acute health risks that cause immediate harm. The purpose of this work is to examine environmental justice in terms of potential acute health risks by examining the distribution of serious chemical accidents across diverse subpopulations. Methods. We draw upon 1990 census data for the United States to study the relationship between the racial, ethnic, and economic characteristics of census block groups ( N = 226,398) and the presence or absence of chemical accidents that caused at least one injury, death, or evacuation for the time period of 1990–1996. The data used to map the location of the chemical accidents were obtained from the Environmental Protection Agency's Accidental Release Information Program (ARIP) database. Results. Our results indicate that the acute risk associated with chemical accidents at fixed facilities is greater for individuals living in low–income census block groups, especially when comparisons are made within the counties where the chemical accidents occur. Our results concerning race and ethnicity are less consistent and somewhat weaker. Conclusions. Although these results do not show large and dramatic effects, as have often been found in the study of the social distribution of chronic environmental risk, they do stand as one of a relatively few social analyses of social variation in exposure to acute environmental risk.     

Job Skill and Black Male Wage Discrimination*

Objective. Debate over the causes of wage inequality have raised suggestions that, rather than discrimination, skill differences may be the reason for racial wage disparities. The purpose of this research is to examine what impact on‐the‐job skill differences have on wage inequality. Method. I regress the log wage onto race and a measure of skill. The Multi‐City Study of Urban Inequality Employer Survey is particularly useful in this analysis because it contains the employer's evaluation of the worker's relative skill against other workers. Result. When white and black men have the same employer's competitive performance rating, rather than decreasing racial wage differences, the differences actually increase. Conclusion. The wage gap is not a skills gap, but evidence of racial discrimination in the labor market.     

An interesting property of the Poisson operating characteristic function

In elementary probability theory, as a result of a limiting process the probabilities of aBi(n, p) binomial distribution are approximated by the probabilities of aPo(np) Poisson distribution. Accordingly, in statistical quality control the binomial operating characteristic function \(\mathcal{L}_{n,c} (p)\) is approximated by the Poisson operating characteristic function \(\mathcal{F}_{n,c} (p)\) . The inequality \(\mathcal{L}_{n + 1,c + 1} (p) > \mathcal{L}_{n,c} (p)\) forp∈(0;1) is evident from the interpretation of \(\mathcal{L}_{n + 1,c + 1} (p)\) , \(\mathcal{L}_{n,c} (p)\) as probabilities of accepting a lot. It is shown that the Poisson approximation \(\mathcal{F}_{n,c} (p)\) preserves this essential feature of the binomial operating characteristic function, i.e. that an analogous inequality holds for the Poisson operating characteristic function, too.     

The Sample Coefficient of Determination in Simple Linear Regression

The behavior of the sample coefficient of determination is examined for some arrangements of independent variable values in a simple linear regression with normally distributed error terms. Numerical values of means and standard deviations are presented that provide some insight into the influence of range and arrangement of independent variable values and sample size on the size of the sample coefficient of determination. Some asymptotic results are given.     

Nonlinear unbiased estimation in linear models †

In the paper the problem of nonlinear unbiased estimation of expectation in linear models is considered. The considerations are restricted to linear plus quadratic estimators with quadratic parts invariant under a group of translations. The one way classification model is considered in detail, for which an explicit formula for the locally best estimators is presented. A numerical evaluation of variances of the best estimators is given for some unbalanced one way classification models and compared with the variance of the ordinary linear estimators.     

An Alternative to Transfer Function Forecasting Based on Subspace Methods

In the time series literature, recent interest has focused on the so-called subspace methods. These techniques use canonical correlations and linear regressions to estimate the system matrices of an ARMAX model expressed in state space form. In this article, we use subspace methods to forecast two series with the help of some exogenous variables related to them. We compare the results with those obtained using traditional transfer function models and find that the forecasts obtained with both methods are similar. This result is very encouraging because, in contrast to transfer function models, subspace methods can be considered as almost automatic.