The diagnostic tools examined in this article are applicable to regressions estimated with panel data or cross-sectional data drawn from a population with grouped structure. The diagnostic tools considered include (a) tests for the existence of group effects under both fixed and random effects models, (b) checks for outlying groups, and (c) specification tests for comparing the fixed and random effects models. A group-specific counterpart to the studentized residual is introduced. The methods are illustrated using a hedonic housing price regression. 相似文献
The relationship between the concentration ellipsoid of a random vector and its planes of support is exploited to provide a geometric derivation and interpretation of existing results for a general form of the linear regression model. In particular, the planes of support whose points of tangency to the ellipsoid are contained in the range (or column space) of the design matrix are the source of all linear unbiased minimum variance estimators. The connection between this idea and estimators based on projections is explored, as is also its use in obtaining and interpreting some existing relative efficiency results. 相似文献
The empirical likelihood (EL) technique has been well addressed in both the theoretical and applied literature in the context of powerful nonparametric statistical methods for testing and interval estimations. A nonparametric version of Wilks theorem (Wilks, 1938
Wilks , S. S. ( 1938 ). The large-sample distribution of the likelihood ratio for testing composite hypotheses . Annals of Mathematical Statistics 9 : 60 – 62 .[Crossref], [Google Scholar]) can usually provide an asymptotic evaluation of the Type I error of EL ratio-type tests. In this article, we examine the performance of this asymptotic result when the EL is based on finite samples that are from various distributions. In the context of the Type I error control, we show that the classical EL procedure and the Student's t-test have asymptotically a similar structure. Thus, we conclude that modifications of t-type tests can be adopted to improve the EL ratio test. We propose the application of the Chen (1995
Chen , L. ( 1995 ). Testing the mean of skewed distributions . Journal of the American Statistical Association 90 : 767 – 772 .[Taylor & Francis Online], [Web of Science ®], [Google Scholar]) t-test modification to the EL ratio test. We display that the Chen approach leads to a location change of observed data whereas the classical Bartlett method is known to be a scale correction of the data distribution. Finally, we modify the EL ratio test via both the Chen and Bartlett corrections. We support our argument with theoretical proofs as well as a Monte Carlo study. A real data example studies the proposed approach in practice. 相似文献
Harley (1954) gave asymptotic expansions for the distributio function and for percentiles of the distribution of the bivariate normal sample correlation coefficient. To the stated order of approximation these expansions were incomplete in that contributions from some higher cumulants were not taken into account. In this article the completed expansions are given together with an asymptotic expansion yielding approximate confidence limits for the population correlation coefficient. Numerical comparisons indicate that asymptotic expansions are superior to other suggested approximate methods 相似文献
Play offers rich opportunities for toddlers to develop motor, social, cognitive, and language skills, particularly during interactions with adult caregivers who may scaffold toddlers to higher levels of play than toddlers achieve on their own. However, research on play has narrowly focused on children from White, middle‐income backgrounds, leaving a dearth of knowledge about dyadic play in diverse cultural communities. We videorecorded 222 Mexican‐American mothers playing with their 2‐year‐old toddlers with a standard set of toys. Play behaviors were coded as nonsymbolic or symbolic (play type) and as expressed through manual, verbal, or multiple channels (play modality). Play between toddlers and mothers was frequent, high in symbolic content, and toddler play closely corresponded with mother play in type and modality: Toddlers’ nonsymbolic play related to mothers’ nonsymbolic play; toddlers’ symbolic play related to mothers’ symbolic play; toddlers’ manual play related to mothers’ manual play; and toddlers’ multimodal play related to mothers’ multimodal play. Play in Mexican‐American mothers and toddlers is frequent, multimodal, and symbolically rich, offering new directions for future research and practice. 相似文献
Using eight two-year panels from the Medical Expenditure Panel Survey data for the period 2004 to 2012, we examine the effect of economic shocks on mental health spending by families with children. Estimating two-part expenditure models within the correlated random effects framework, we find that employment shocks have a greater impact on mental health spending than do income or health insurance shocks. Our estimates reveal that employment gains are associated with a lower likelihood of family mental health services utilization. By contrast employment losses are positively related to an increase in total family mental health. We do not detect a link between economic shocks and mental health spending on behalf of fathers.
ABSTRACT Shared memories shape relations among social movement participants and their organizations. However, scholars often ignore how experience operates as a means of solidifying attachment in group contexts. In contrast, I argue that activism depends on how participants publicly recall events. In this, I integrate a social memory perspective with the examination of activist movements. Through narrative, participants build engagement by presenting the self-in-history as a model for collective action. I refer to this as eventful experience, utilizing memorable moments as a resource for generating commitment. Movements depend upon members communicating the critical moments of their lives, embedding personal timelines in group culture. The linkage of personal experience and public events is a strategy by which individuals motivate collective action. Drawing on a thirty-month ethnography of a progressive senior citizen activist group in Chicago, I examine how members use an awareness of temporality to build a culture of action. Each movement group uses the past experiences of participants to build their culture – what Jasper refers to as taste in tactics, incorporating past successes, present plans, and imagined futures into a call for direct action. 相似文献
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Interest in collaboration between government and private, grantmaking foundations has grown considerably in recent years... 相似文献
This article considers Bayesian inference in the interval constrained normal linear regression model. Whereas much of the
previous literature has concentrated on the case where the prior constraint is correctly specified, our framework explicitly
allows for the possibility of an invalid constraint. We adopt a non-informative prior and uncertainty concerning the interval
restriction is represented by two prior odds ratios. The sampling theoretic risk of the resulting Bayesian interval pre-test
estimator is derived, illustrated and explored.
The authors are grateful to the editor and the referee for their helpful comments. 相似文献