摘要:

AbstractThe purpose of this paper is to assess the consistency of the historic record of mean global temperature with a climate model of historic greenhouse warming. Because there is no natural parametric alternative to the climate model, goodness‐of‐fit is assessed via nonparametric regression. While the historic record is not consistent with the model with high temperature sensitivity, it is not inconsistent with the model using the best‐fitting temperature sensit

ISSN:1180-4009    

DOI:10.1002/env.3170030401

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractMethods are presented for assessing interactions and other effects between genetic and environmental factors for human disease or cancer susceptibility. Statistical estimation and testing approaches are based on a simple multinomial sampling model for the case‐control sampling scenario. It is noted that logistic regression methods can facilitate computation of likelihood‐based statistics in this setting. Additional models for collapsibility over genotypes within the genetic factor are considered. Monte Carlo comparisons show that the method appears to retain nominal significance levels at total sample sizes above 100. At smaller sample sizes, a goodness‐of‐fit statistic is suggested for testing the interactive effect between the genetic and environmental

ISSN:1180-4009    

DOI:10.1002/env.3170030402

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractKendall's tau is often used to detect the presence of trend in environmental time series data. Assuming stationarity, a general expression for the variance of the associatedSscore is derived. The results are specialized to the cases of MA(1) and MA(2). Asymptotic normality of tau is established. It is shown that the variance of tau is strongly affected by the assumption of statistical dependence. A seasonal model with non‐zero correlations between successive seasons and years is considered. Simulation results indicate that the effects of departures from distributional assumptions are less important when compared to the effects of departures from the independence assumptio

ISSN:1180-4009    

DOI:10.1002/env.3170030403

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this report, we examine acid wet deposition data collected sequentially in time at multiple monitoring stations. The key objective here is to give a reasonable description of the overall trend pattern of the wet deposition of sulfate. We proceed by first modelling the data collected at each individual station to obtain individual trend estimates at that particular station and then pooling together these trend components by means of a multiple random effects model. Our conclusion is that the overall trend in the United States exhibits a U‐shap

ISSN:1180-4009    

DOI:10.1002/env.3170030404

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA stochastic model is developed to characterize flow, adsorption and transport of solute molecules through the solid phase in an open flow adsorber. The flow process is depicted as composed ofncompartments with forward and backward flow connecting adjacent compartments. To account for adsorption and transport of solute molecules through the porous solid, the solid phase in each compartment is partitioned into an outer layer and an inner layer. The stochastic process model accounts for movement of solute molecules in the liquid phase, for the transfer of molecules between the liquid and the outer layer of the solid phase and for solute movement through the solid phase. From this model, one may predict the residence time distribution of a molecule in the system and the concentration profile of solute molecules in the outlet stream (breakthrough curve) and estimate the adsorption and flow parameters of the process. In addition to its usefulness in engineering treatment systems such as water and air purification, this modelling approach is useful in studying the transport of organic chemicals in the soil.

ISSN:1180-4009    

DOI:10.1002/env.3170030405

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA new class of probability distributions is introduced. This class accentuates the periodic behaviour of environmental conditions in time and the random occurrence of some events on each period. A constructive approach is used following the logic of the appearance of random events in the evolution of real‐world systems. Some physical and probabilistic properties of the new distributions are discussed. Elementary statistical data models are considered and two types of estimations of the attributes of these distributions are offered. Numerical and graphical illustrations with simulated and observed data are used to motivate our suggestion

ISSN:1180-4009    

DOI:10.1002/env.3170030406

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractSince the final results of a comparative intervention (environmental or clinical) trial are usually in doubt at an interim analysis, it is necessary to quantify the uncertainty associated with data yet to be observed. A natural way of quantifying such uncertainty is the Bayesian predictive distribution. The use of such a distribution requires an investigator to specify his opinions in the form of a prior distribution. We reference how this distribution may be obtained by eliciting opinions from an investigator. Further, the methodology is applied to determine an appropriate stopping rule in an experiment to compare survival times of two treatments. This is done by deriving the probability that the ratio of mean or total survival times given the current sample size exceeds a given fixed value. If this probability is below a certain specified value, a dynamic estimate of the required additional sample size may be obtained. We show examples from cancer clinical trials.

ISSN:1180-4009    

DOI:10.1002/env.3170030407

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY