Confidence interval estimation for the population coefficient of variation using ranked set sampling: a simulation study

In this paper, an evaluation of the performance of several confidence interval estimators of the population coefficient of variation (τ) using ranked set sampling compared to simple random sampling is performed. Two performance measures are used to assess the confidence intervals for τ, namely: width and coverage probabilities. Simulated data were generated from normal, log-normal, skew normal, Gamma, and Weibull distributions with specified population parameters so that the same values of τ are obtained for each distribution, with sample sizes n=15, 20, 25, 50, 100. A real data example representing birth weight of 189 newborns is used for illustration and performance comparison.     

Social capital and public goods

Previous literature suggests positive relationships between social capital, pro-social behavior and subsequent economic development. We analyze the relationship between social networks and trust (two measures of social capital) and self-reported charitable contributions of time and/or money (pro-social behavior) using data collected from two ethnically distinct, low-income neighborhoods. We find that large social networks are positively related to charitable contributions, but that the effects of trust are less robust. We also find that social networks that are more geographically dispersed tend to be larger. Our results indicate that the social capital in a neighborhood is more important than ethnicity, ethnic diversity, or other demographic information in understanding public goods contributions.     

Teaching History That Functions for Daily Living

As the development of active, democratic citizens has become, arguably, the primary purpose of social studies education, the model of instruction in citizenship education varies significantly. Although current models of citizenship education typically foster a sense of societal conformity and law-obeyance to the exclusion of social change, this article illustrates how elementary school students engaged in the critical examination of a pertinent social issue and guided the direction of a social action plan devised to overcome the injustice of bullying. The focus of this article is to illustrate how one fourth-grade teacher harnessed her students’ enthusiasm and interest in activism through an inquiry-based, interdisciplinary social action unit devised to solve elementary school bullying. A detailed, step-by-step narrative of the unit is described.     

Estimating multivariate random effects without replication

This paper considers the estimation of multivariate random effects that are measured with error, but for which there are no replications. Using structural simplification of the correlation of the data, separate estimates are generated for the covariance of the random effects and the covariance of the error. An estimator of the random effects based on a truncated eigen structure is defined, and matrix mean squared error and its trace (risk) are analyzed, with comparison to the maximum likelihood estimator (m.l.e) and also to the Stein-like estimator of Efron and Morris (1972). It is shown that the estimator has risk which is smaller than the risk of the maximum likelihood estimator and the Efron-Morris estimator in most cases.     

Research Methodology and Community Participation: A Decade of Indigenous Social Science Research in Canada

Those engaged in community‐based participatory research often comment on tensions between social scientific and community values, yet little systematic evidence exists about the relationship between social science research methodologies and community participation. We analyze nearly 500 peer‐reviewed articles published between 2005 and 2015 on Indigenous issues in Canada, where policies encourage participatory research methods with disempowered groups. We find that research that includes Indigenous participation is more likely to include Indigenous epistemologies and participatory evidence sources and analysis methods. We also find that peer‐reviewed research involving Indigenous participants often fails to go beyond minimum levels of consultation required by policies.     

Application of the Precautionary Principle by Senior Policy Officials: Results of a Canadian Survey

Though use of the controversial precautionary principle in risk management has increasingly been recommended as a guide for the construction of public policy in Canada and elsewhere, there are few data available characterizing its use in risk management by senior public policymakers. Using established survey methodology we sought to investigate the perceptions and terms of application of the precautionary principle in this important subset of individuals. A total of 240 surveys were sent out to seven departments or agencies in the Canadian government. The overall survey response rate was 26.6%, and our findings need to be interpreted in the context of possible responder bias. Of respondents, the overwhelming majority perceived the precautionary principle and the management of risk as complementary, and endorsed a role for the precautionary principle as a general guideline for all risk management decisions. However, 25% of respondents responded that the lack of clarity of the definition of the principle was a limitation to its effective use. The majority of respondents viewed their own level of understanding of the precautionary principle as moderate. Risk managers appeared to favor an interpretation of the precautionary principle that was based on the seriousness and irreversibility of the threat of damage, and did not endorse as strongly the need for cost effectiveness in the measures taken as a precaution against such threats. In contrast with its perceived role as a general guideline, the application of the precautionary principle by respondents was highly variable, with >60% of respondents reporting using the precautionary principle in one-quarter or less of all risk management decisions. Several factors influenced whether the precautionary principle was applied with the perceived seriousness of the threat being considered the most influential factor. The overwhelming majority of risk managers felt that "preponderance of evidence" was the level of evidence required for precautionary action to be instituted against a serious negative event. Overall, the majority of respondents viewed the precautionary principle as having a significant and positive impact on risk management decisions. Importantly, respondents endorsed a net result of more good than harm to society when the precautionary principle was applied to the management of risk.     

Hypothesis Testing in Multivariate Linear Models with Randomly Missing Data

Tests for mean equality proposed by Weerahandi (1995) and Chen and Chen (1998), tests that do not require equality of population variances, were examined when data were not only heterogeneous but, as well, nonnormal in unbalanced completely randomized designs. Furthermore, these tests were compared to a test examined by Lix and Keselman (1998), a test that uses a heteroscedastic statistic (i.e., Welch, 1951) with robust estimators (20% trimmed means and Winsorized variances). Our findings confirmed previously published data that the tests are indeed robust to variance heterogeneity when the data are obtained from normal populations. However, the Weerahandi (1995) and Chen and Chen (1998) tests were not found to be robust when data were obtained from nonnormal populations. Indeed, rates of Type I error were typically in excess of 10% and, at times, exceeded 50%. On the other hand, the statistic presented by Lix and Keselman (1998) was generally robust to variance heterogeneity and nonnormality.