ISSN:1180-4009    

DOI:10.1002/env.3170010102

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:1180-4009    

DOI:10.1002/env.3170010103

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractWe examine four core methods and principles of statistical inference and discuss implications among them. This leads to the consideration of some recent methods of obtaining distributions for inference concerning an interest parameter, free of nuisance parameters. A concluding section discusses some current methods for approximating the needed distributions.

ISSN:1180-4009    

DOI:10.1002/env.3170010104

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:1180-4009    

DOI:10.1002/env.3170010105

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:1180-4009    

DOI:10.1002/env.3170010106

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe problem of acid rain deposition has generated much interest in the modelling and estimation of the effects of acid rain. Recent studies in the northeastern United States have focused on the question of trends in lake acidity and the effects on aquatic organisms, especially fish. One approach has been to model the presence or absence of fish species as a function of relevant environmental variables. As the number of these explanatory variables may be large, there is concern about redundancies and collinearities. Because the model used is a special case of generalized linear models, standard approaches to assessment and adjustment for collinearity may be misleading. Estimation of parameters in the generalized linear model involve an interative method of solution. The important parameter is the information matrix. Illconditioning of this matrix, as caused by collinearity has severe effects on parameter and variance estimates. To asssess the effects of collinearities, some new diagnostics are presented. Two techniques for estimating parameters in the presence of multicollinearity; the ridge estimator and the principal component method, are extended to the generalized linear model.

ISSN:1180-4009    

DOI:10.1002/env.3170010107

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA survey of 1,189 lakes was conducted in the fall of 1987 as part of the Finnish Research Project on Acidification (HAPRO). Most of the lakes for the survey(n=987) were randomly selected by a two‐stage cluster sampling from two separate subregions, together covering the whole country. Lakes of sizes 0.01‐10 km2were included in the statistical sampling of the southern and central regions (Subregion 1). In northern Finland (Subregion 2) only lakes of sizes 0.1‐10 km2were included. The statistical sampling “frame” in each subregion consisted of the number of lakes in the grid net formed from a series of topographic maps with a scale of 1:50,000 (20X30 km2). The total number of maps was 472 in Subregion 1 and 175 in Subregion 2. In the first sampling stage, 100 maps were selected from Subregion 1 and 25 maps from Subregion 2, using the “probability proportional to size (pps)” method, selection of the maps being weighted by lake density. In the second sampling stage, all of the lakes with a size within the determined size range were numbered and eight lakes chosen by systematic random sampling from each previously selected map. A further 202 mainly head water lakes examined in previous acidification studies were also included. Water samples were taken from the surface layer (1m) of the lakes during fall overturn in 1987. An extensive analytical program was carried out on each lake‐water sample. Major watershed characteristics have been determined from topographic and soil maps. The statistically based survey design allows estimates to be made of the proportion of lakes fulfilling any predetermined criteria and the corresponding variances. The number of acidic (acid neutralizing capacity (ANC) ⩽ 0 μeq L‐1) lakes in Finland was e

ISSN:1180-4009    

DOI:10.1002/env.3170010108

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractLove Canal is a 6.4 hectare tract, originally an uncompleted power canal, which was used for disposal of industrial chemicals in the 1940's and 1950's. The canal was later filled, and a school and residences were built on the site. Following a highly publicized discovery of contaminant migration from the canal in the 1970's, the school and nearby homes were demolished. Determination of the habitability of about 800 homes evacuated by Presidential order in 1980 in the surrounding Love Canal Emergency Declaration Area (EDA), was a highly visible environmental policy decision. The soil habitability study for the EDA was based on two‐sample comparisons of concentrations of eight trace organic indicators (Love Canal Indicator ChemicalsMdashLCICs) in EDA neighborhoods with selected comparison areas (CAs). The power of the statistical procedure (s) was an explicit criterion in the design of the study on which the habitability decision was based.Monte Carlo experiments were used to evaluate the relative performance of candidate statistical tests. The Monte Carlo simulations led to a recommendation for a pilot study to better identify the statistical characteristics of the soil chemical data. Analysis of the pilot study data, collected in the spring of 1986, suggested 1) that Monte Carlo experiments should be focused on univariate and multivariate Wilcoxon tests, 2) that a log normal mixture distribution provided reasonable fits to the observed data and could be used to evaluate a wide range of alternative hypotheses, and 3) that between‐laboratory variation would have to be explicitly addressed by the statistical test(s) and in experimental design. The test that was finally selected was a generalization of the Wilcoxon rank sum test for blocking by laboratory.The univariate (single chemical) and multivariate (multiple chemical) blocked Wilcoxon tests were applied to all combinations of EDA sampling areas and comparison areas using field data collected in the fall of 1987. For most comparisons and chemicals, the EDA sampling areas were found not to have significantly higher soil LCIC concentrations than the comparison areas. However, a few EDA sampling areas showed consistently higher concentrations for several LCICs. The multivariate test was particularly useful in avoiding the multiple comparison problem with respect to soil chemicals. Based in part on the results of the soil sampling study, the New York State Commissioner of Health, in September 1988, identified EDA neighborhoods that were suitable for rehabitation. Although the decision was made in a policy framework, the specific recommendations were consistent with the results of the statistical analy

ISSN:1180-4009    

DOI:10.1002/env.3170010109

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractIn an occupational study of death certificates in the Swiss mortality register in the years 1969‐1983, the mortality experience from malignancies of the haematopoietic and lymphatic systems (abbreviated as MHLS, 8th ICD: 200‐209) among railway engine drivers and two reference categories was analyzed. The reference groups included professions of metal construction and machine building (CI) and technical personnel (C2) respectively. For the railway engine drivers, assumed to be long‐term exposed to extremely low frequency electromagnetic fields (ELF), a total of 70,000 man‐years were observed, for C1 and C2 the number of years under observation were 900,000 and 1.56 million respectively. Railway engine drivers showed slightly elevated mortality ratios in comparison to C1: PMR=144, 95% confidence interval=91‐217, SMR=108, CI=69‐163. Comparison against C2 showed statistically significant increased mortality ratios, PMR=163, CI=103‐244, SMR=171, CI=109‐257. Analysis of all causes of mortality showed that railway engine drivers provide a lower support to the hypothesis that exposure to ELF may

ISSN:1180-4009    

DOI:10.1002/env.3170010110

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:1180-4009    

DOI:10.1002/env.3170010101

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY