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The traditional estimation of higher order co-moments of non-normal random variables by the sample analog of the expectation faces a curse of dimensionality, as the number of parameters increases steeply when the dimension increases. Imposing a factor structure on the process solves this problem; however, it leads to the challenging task of selecting an appropriate factor model. This paper contributes by proposing a test that exploits the following feature: when the factor model is correctly specified, the higher order co-moments of the unexplained return variation are sparse. It recommends a general to specific approach for selecting the factor model by choosing the most parsimonious specification for which the sparsity assumption is satisfied. This approach uses a Wald or Gumbel test statistic for testing the joint statistical significance of the co-moments that are zero when the factor model is correctly specified. The asymptotic distribution of the test is derived. An extensive simulation study confirms the good finite sample properties of the approach. This paper illustrates the practical usefulness of factor selection on daily returns of random subsets of S&P 100 constituents. 相似文献
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The use of lower probabilities is considered for inferences in basic jury scenarios to study aspects of the size of juries and their composition if society consists of subpopulations. The use of lower probability seems natural in law, as it leads to robust inference in the sense of providing a defendant with the benefit of the doubt. The method presented in this paper focusses on how representative a jury is for the whole population, using a novel concept of a second ’imaginary’ jury together with exchangeability assumptions. It has the advantage that there is an explicit absence of any assumption with regard to guilt of a defendant. Although the concept of a jury in law is central in the presentation, the novel approach and the conclusions of this paper hold for representative decision making processes in many fields, and it also provides a new perspective to stratified sampling. 相似文献
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Sophie Mitra Kris Jones Brandon Vick David Brown Eileen McGinn Mary Jane Alexander 《Social indicators research》2013,110(3):1061-1081
Recently, there have been advances in the development of multidimensional poverty measures. Work is needed however on how to implement such measures. This paper deals with the process of selecting dimensions and setting weights in multidimensional poverty measurement using qualitative and quantitative methods in a participatory framework. We estimate the multidimensional poverty measures developed by Alkire and Foster for a particular group: persons with psychiatric diagnoses in the United States. To select relevant dimensions and their relative ordering, two discussion groups are convened: one consisting of persons with lived-experience expertise and the other consisting of people with mental health service provision or research expertise. Several methods are used to convert dimension rankings into weights. The selection and ordering of dimensions differed between the two discussion groups, as did the resulting poverty measures. For instance, the poverty headcount using the dimensions and weights of the ‘lived experience’ group ranged from 20.61 to 26.96% as compared to a range of 18.62–33.19% using those of the ‘provider/researcher’ group. One of the main results of this study is that the Alkire Foster method is sensitive to the selection of dimensions and the methods used to derive rankings and weights. It points toward the limitation of relying exclusively on small scale qualitative methods for the selection and ranking of dimensions. In addition, the participatory framework used in this study was found to be essential in interpreting results, in particular with respect to the limitations of the data set in measuring relevant dimensions. 相似文献
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This study explored the relationship of both romantic and platonic involvement with boys, as well as pubertal status, to body image and depression symptoms among an ethnically diverse sample of sixth‐grade girls. Participants were 157 early adolescent girls (ages 10–13) who completed self‐report measures designed to assess girls' level of involvement with boys, pubertal status, and psychological adjustment. Girls' degree of romantic involvement was positively associated with higher depression scores. More advanced pubertal status was associated with both lower body image satisfaction and higher depression scores. A significant interaction between platonic involvement and pubertal status emerged. Girls who were less sexually mature but who also reported more platonic involvement with boys reported greater body image satisfaction. These findings suggest that the type of involvement with boys (romantic vs. platonic) and a girl's pubertal status influence psychological adjustment. 相似文献
5.
F. P. A. Coolen P. Coolen-Schrijner T. Coolen-Maturi F. F. Elkhafifi 《统计学通讯:理论与方法》2013,42(19):3478-3496
Nonparametric predictive inference (NPI) is a powerful frequentist statistical framework based only on an exchangeability assumption for future and past observations, made possible by the use of lower and upper probabilities. In this article, NPI is presented for ordinal data, which are categorical data with an ordering of the categories. The method uses a latent variable representation of the observations and categories on the real line. Lower and upper probabilities for events involving the next observation are presented, and briefly compared to NPI for non ordered categorical data. As application, the comparison of multiple groups of ordinal data is presented. 相似文献
6.
Alicia VandeVusse Kris Rosentel Lawrence Coldon III John Schneider Brandon J. Hill 《Journal of gay & lesbian social services》2020,32(3):283-296
AbstractThe purpose of this exploratory study was to examine the prevalence of parenting and child-caretaking among a sample of black men who have sex with men (MSM), as well as associations between parenting roles and sexual and reproductive health (SRH) factors. Parenting and SRH data were derived from a survey of 199 black MSM. Nearly half of the sample reported being a father or father-figure (44.4%), almost a third indicated serving as caretaker of a child (29.1%), and one in five have a biological child (20.1%). Over half of the sample reported at least one of these three parenting/child-caretaking roles (52.5%). Two significant differences were observed for sexual health variables: men with biological children were significantly more likely to report using condoms inconsistently (55.0% vs. 35.7%, p = .026) and engaging in transactional sex work (36.8% vs. 21.0%, p = .041). Given the observed prevalence, parenting and child-caretaking among black MSM warrant further inquiry as factors that may influence SRH outcomes and care utilization. Services and interventions tailored to black MSM should consider these men’s potential roles and responsibilities as parents and caretakers of children. 相似文献
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Kirstin R. Painter Maria Scannapieco Gary Blau Amy Andre Kris Kohn 《Journal of social service research》2018,44(2):223-235
ABSTRACTThe purpose of this groundbreaking study was to evaluate outcomes of 482 LGBTQ (lesbian, gay, bisexual, transgender, or questioning) youth and young adults who received services and supports through the Comprehensive Community Mental Health Services for Children with Serious Emotional Disturbances Program (CMHI). This study was a secondary data analysis using data from a larger study of 3208 LGBTQ and non-LGBTQ youth ages 11 through 21 who had a serious emotional disturbance (SED). This study is significant in that it evaluates functional outcomes for young people identified as LGBTQ based on a specialized service framework (i.e., system of care approach). In essence, do LGBTQ youth with SED benefit from a specific approach to intervention? In addition, a comparison at intake on suicidality, bullying and victimization was conducted between the LGBTQ and non-LGBTQ identifying youth from the larger sample. The youth and a caregiver were interviewed face-to-face separately at intake, 6-months, and 12-months. Significant improvements were found across all of the dependent variables, supporting the viability of SOC for improving outcomes for LGBTQ youth. Future research should continue to build on this study by adding to the design a control group to improve internal validity of the findings. 相似文献
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Using original data from the Northern Ireland Life and Times survey, this article assesses public attitudes toward key issues of symbolism intimately connected with the Northern Ireland conflict and peace process. It uses public attitudes toward the symbolic expressions of Northern Ireland's politico-religious blocs as indicators of the extent of intercommunity tolerance in the delicate post-Belfast Agreement period. Survey questions on attitudes toward flags, including the idea of a new flag for Northern Ireland; loyalist and republican murals; and memorials to the dead of the conflict, including the idea of a memorial for all of the victims of the conflict, reveal that partisan attitudes toward communal symbols of identity and commemoration persist, despite macro-level political changes heralded by the 1998 peace accord. It is argued that the consociational design of the Belfast Agreement facilitates the perpetuation of the single-identity politics of Irish nationalism and Ulster unionism. In this context, public attachment to partisan symbols remains strong. 相似文献
10.
Boudt Kris Rousseeuw Peter J. Vanduffel Steven Verdonck Tim 《Statistics and Computing》2020,30(1):113-128
Statistics and Computing - The minimum covariance determinant (MCD) approach estimates the location and scatter matrix using the subset of given size with lowest sample covariance determinant. Its... 相似文献