Differences in consumption patterns of single-parent and two-parent families in the United States

Different patterns of single-parent and two-parent families in six major expenditure categories are examined using the 1989 Consumer Expenditure Survey. Comparisons are made of the influence of permanent income, family size, region, race, gender, age, and education of the head of the family on the expenditure categories. The results show that with the exception of expenditures on shelter, the two groups differ significantly in their consumption patterns.1991 Visiting Professor at the Family Economics Research Group, Agricutural Research Service, U.S. Department of Agriculture. Current research interests include consumption economics and time-use allocation.Current research interests include the economic status of American households.     

Promoting online media relations: Public relations departments’ use of Internet in the UAE

This paper discusses the use of Internet by public relations departments in the United Arab Emirates, to reach their key publics online and to gather information and monitor data to perform their tasks and to promote and develop their relations with the news media. Findings of the study show that all 24 organizations have a homepage, but only two thirds of them are posting their publications on the net, and only one third are using electronic newspapers to monitor their coverage in the media and to gather news, data and information of importance for the various tasks they perform. Only three organizations out of 24 have an online newsroom, and only two have a virtual tour about the organization. None of the surveyed organizations’ Web site has a film or videos. Organizations in the United Arab Emirates still have a lot to do to take advantage fully and rationally of what interactive communication, Internet and online publications are offering for a better performance and more effective public relations.     

Patterns of Spending Behavior and the Relative Position in the Income Distribution: Some Empirical Evidence

A model integrating the permanent income and relative income hypotheses was employed to explain consumer expenditure behavior in the U.S. The model was empirically tested using data from the interview survey portion of the 1996 and 1997 Consumer Expenditure Survey. The results indicate that household expenditure behavior is generally explained by both hypotheses when integrated in one model.     

Annual mortality rates and excess deaths of children under five in Iraq, 1991-98

Data from two parallel household surveys conducted in Iraq by UNICEF in 1999 show that under-5 mortality declined steadily from 1974 to 1990, reaching about 63 per 1,000 live births in the period 1986-90. It then rose dramatically to 118 per 1,000 in 1991, the year of the Gulf War. The number of 'excess' under-5 deaths (i.e., the number in excess of the number predicted from past trends) in Iraq between 1991 and 1998 was calculated assuming that, instead of the rates measured by the 1999 survey for this period, either (a) average mortality rates for the period 1986-90 had been maintained, or (b) mortality had continued to decline at the rate observed between 1974 and 1990. According to these calculations, the estimated number of excess deaths resulting from the Gulf War and its aftermath up to 1998 was between 400,000 (assumption a) and 500,000 (assumption b).     

Outlier Detection in a Circular Regression Model Using COVRATIO Statistic

In this article, we model the relationship between two circular variables using the circular regression models, to be called JS circular regression model, which was proposed by Jammalamadaka and Sarma (1993). The model has many interesting properties and is sensitive enough to detect the occurrence of outliers. We focus our attention on the problem of identifying outliers in this model. In particular, we extend the use of the COVRATIO statistic, which has been successfully used in the linear case for the same purpose, to the JS circular regression model via a row deletion approach. Through simulation studies, the cut-off points for the new procedure are obtained and its power of performance is investigated. It is found that the performance improves when the resulting residuals have small variance and when the sample size gets larger. An example of the application of the procedure is presented using a real dataset.     

Efficiency estimation of type-I censored sample from the Weibull distribution based on sup-entropy

On the basis of Awad sup-entropy, the efficiency function for type-I censored sample from the Weibull distribution is numerically introduced. The properties of the derived efficiency are discussed. Furthermore, for a given efficiency, the termination time of the experiment, and the maximum likelihood estimates for the Weibull parameters, are proposed. Simulation results are tabulated and discussed. Censored and complete samples are compared for a wide range of the efficiency. The comparisons show the quality of the developed algorithms and the effectiveness of using censoring in estimating with the Weibull distribution.     

Semantic network representation of computer-mediated discussions: Conceptual facilitation form and knowledge acquisition

Prior research on computer-mediated discussions examined their effects on knowledge acquisition without considering the role of the discussion representation. In this study, we investigate and compare the effect of semantic network discussion representations on knowledge acquisition to that of the threaded representations featured in most traditional discussion forums. Furthermore, we identify, define and operationalize a new, i.e., conceptual facilitation (validation of the conceptual organization of the discussion), assessing its role in knowledge acquisition at different levels of restrictiveness. The empirical results of a field experiment indicate that semantic network discussion representations enable the acquisition of more complex and better-integrated knowledge structures than threaded discussion representations. Conceptual facilitation forms entailing different levels of restrictiveness are also found to play a significant role. As the level of conceptual facilitation restrictiveness decreases, knowledge acquisition improves. Our findings empirically demonstrate the importance of accounting for discussion representation as a contingency factor in explaining group discussion processes and outcomes. To practitioners, our study provides empirical evidence on the advantages of semantic networks over threaded representations as an alternative mode for computer-mediated discussion representations. We also suggest guidelines for the selection of appropriate conceptual facilitation for discussion forums intended for knowledge acquisition.     

Bayesian estimation of an AR(1) process with exponential white noise

The object of this paper is a Bayesian analysis of the autoregressive model X _t ?=?ρX _t?1?+?Y _t where 0?Y _t are independent random variables with an exponential distribution of parameter θ. Our study generalizes some results obtained by Turkmann (1990 Amaral Turkmann, M. A. (1990). Bayesian analysis of an autoregressive process with exponential white noise. Statistics, 4: 601–608.  [Google Scholar]). Our analysis is based on a more general non-informative prior which allows us to improve the estimators of ρ and θ.     

A New Test of Discordancy in Circular Data

In this article, we present an alternative test of discordancy in samples of univariate circular data. The new technique is based on the effect of existence of an outlier on the summation of circular distances of the point of interest to all other points. The percentage points are calculated and the performance is examined. We compare the performance of the test in detecting an outlier with other tests and show that the new approach performs relatively better than other known tests. As an illustration a practical example is presented.     

Generalized Linear Factor Models: A New Local EM Estimation Algorithm

In this article, a general approach to latent variable models based on an underlying generalized linear model (GLM) with factor analysis observation process is introduced. We call these models Generalized Linear Factor Models (GLFM). The observations are produced from a general model framework that involves observed and latent variables that are assumed to be distributed in the exponential family. More specifically, we concentrate on situations where the observed variables are both discretely measured (e.g., binomial, Poisson) and continuously distributed (e.g., gamma). The common latent factors are assumed to be independent with a standard multivariate normal distribution. Practical details of training such models with a new local expectation-maximization (EM) algorithm, which can be considered as a generalized EM-type algorithm, are also discussed. In conjunction with an approximated version of the Fisher score algorithm (FSA), we show how to calculate maximum likelihood estimates of the model parameters, and to yield inferences about the unobservable path of the common factors. The methodology is illustrated by an extensive Monte Carlo simulation study and the results show promising performance.