Tests of homogeneity of means and covariance matrices for multivariate incomplete data

Existing test statistics for assessing whether incomplete data represent a missing completely at random sample from a single population are based on a normal likelihood rationale and effectively test for homogeneity of means and covariances across missing data patterns. The likelihood approach cannot be implemented adequately if a pattern of missing data contains very few subjects. A generalized least squares rationale is used to develop parallel tests that are expected to be more stable in small samples. Three factors were varied for a simulation: number of variables, percent missing completely at random, and sample size. One thousand data sets were simulated for each condition. The generalized least squares test of homogeneity of means performed close to an ideal Type I error rate for most of the conditions. The generalized least squares test of homogeneity of covariance matrices and a combined test performed quite well also.Preliminary results on this research were presented at the 1999 Western Psychological Association convention, Irvine, CA, and in the UCLA Statistics Preprint No. 265 (http://www.stat.ucla.edu). The assistance of Ke-Hai Yuan and several anonymous reviewers is gratefully acknowledged.     

Action verbal fluency normative data for the elderly

An emerging body of literature points to the prominent role of the frontal lobes in the retrieval of verbs, whereas production of common and proper nouns arguably is mediated primarily by posterior and anterior temporal regions, respectively. Although the majority of studies examining the neuroanatomic distinctions between verb and noun retrieval have relied on action naming tasks (naming depicted activities, e.g., running) as indicators of verb retrieval abilities, recent studies have utilized an action (verb) verbal fluency measure, the Action Fluency Test (AFT), to assess verb retrieval. Findings from these studies suggest that action fluency is sensitive to the integrity of fronto-subcortical neural circuitry and that it is a valid measure of executive and language functions. The AFT is an easily administered executive function measure, but no normative data for the AFT or other action fluency tasks has been published. This study was undertaken to provide initial AFT normative data for a sample of 145 healthy elderly subjects. As education is significantly correlated with AFT scores, the normative data are stratified by educational level.     

网民对“人祸”事件的道德情绪特点——基于微博大数据研究

本研究采用大数据研究方法,对爬取的"动车事故"发生后40天内的94,562条相关微博进行情感分析,以探讨网民对"人祸"的道德情绪特点,同时对不同群体情绪表达差异进行探讨。结果发现:(1)网民对于动车事故主要表达的道德情绪有:愤怒、鄙视、厌恶、同情和爱。(2)包含不同道德基础的事件与不同的道德情绪相关联;(3)对于愤怒、厌恶和鄙视,男性普遍有更高的表达倾向和表达强度,而女性更倾向于表达爱和同情且强度更高;(4)对于爱和同情,团体VIP用户组表达的可能性和强度都高于其他用户;个体VIP用户比非VIP用户更可能表达愤怒、鄙视和厌恶,而团体VIP用户表达这类情绪的强度最小。研究表明,虚拟网络中人们道德情绪特点依然符合道德基础理论;不同群体在表达道德情绪时的差异性是对道德基础理论相关研究的补充。总言之,数据挖掘技术和情感分析方法是进行情绪研究的有效手段。     

The tune in-and-out model: A random walk and its application to a presidential election survey

The stochastic model for the evolution of preferences proposed by Falmagne, Regenwetter, and Grofman [1997. Journal of Mathematical Psychology, 41, 129-143] and tested by Regenwetter, Falmagne, and Grofman [1999. Psychological Review, 106, 362-384], as well as the alternative Thurstonian model of Böckenholt [Falmagne, J.-C., Regenwetter, M., & Grofman, B. (1997). A stochastic model for the evolution of preferences. In A. A. J. Marley (Ed.), Choice, decision and measurement: Essays in honor of R. Duncan Luce (pp. 113-131). Mahwah, NJ: Lawrence Erlbaum.], gave a good statistical account of attitudinal panel data from the 1992 US presidential election. We show, however, that both models have the defect of underestimating the number of respondents who did not change their order of preference for the candidates across different polls. We present a generalization of Falmagne et al.'s model based on the idea that some individuals may become momentarily impervious to all matters related to the campaign and ‘tune out.’ This behavior could be triggered by some personal reason or by some external event related to the campaign. Like the original model, the resulting model is a random walk, but on an augmented set of states. A respondent in a ‘live’ state behaves as in the previous model, except when receiving a ‘tune-out’ token, which effectively freezes the respondent's preference state until it is reversed by a ‘tune-in’ token. We describe and successfully test the new model on the same 1992 National Election Study panel data as those used by Böckenholt (2002) and Regenwetter et al. (1999).     

Self-esteem is a shared relationship resource: Additive effects of dating partners’ self-esteem levels predict relationship quality

Though self-esteem is known to positively impact individuals’ romantic relationship outcomes and those of their partners, the interactive nature of both partners’ self-esteem levels has not been systematically investigated. Using actor-partner interdependence model analyses we estimated actor, partner, and four types of dyadic effects of self-esteem on relationship quality in a sample of over 500 heterosexual dating couples. Lower self-esteem individuals and their partners reported lower satisfaction and commitment to their relationships than did higher self-esteem individuals and their partners. An additive effect whereby both partners’ self-esteem levels combine to predict relationship quality best described the dyadic effects. Results highlight the importance of considering the interactive nature of individual characteristics in dyadic research.     

Use of correlational data to examine the effects of risk perceptions on precautionary behavior

Abstract

The idea that perceptions of high personal risk lead people to adopt precautionary behavior (the “motivational hypothesis”) is mainly tested with correlational data. A review of studies from selective journals reveals a high proportion with methodological and conceptual problems that make them invalid as tests of this hypthesis. Three problems arc emphasized: (1) the misinterpretation of correlations from cross-sectional studies as testing the motivational hypothesis when they actually indicate the accuracy of risk perceptions; (2) the failure to control for prior behavior in prospective studies; and (3) the we of prospective studies in situations of little behavior change. Path models are used to help explain these problems. Recommendations for selecting research designs and for calculating the least problematic correlations are given, along with warnings about the many assumptions needed to interpret even these correlations.

Summary

Overall, 27 of the 61 cross-sectional analyses listed in Tables 2 and 3 were conducted using clearly inappropriate variables. The appropriateness of the remaining correlations rest on one or two rather questionable assumptions: (1) that people do not distort their risk perceptions to justify their behavior or intentions and (2) that negative screening results a problem like breast cancer do not affect perceptions of future risk. The correlations preferred for testing the motivational hypothesis are listed in Table 4.

Summary

When the amount of precautionary behavior in a population has become relatively stable and behavior at time t+1 is well-predicted from behavior at time t, no independent variable other than B_t will have much predictive value in a prospective design. To avoid this problem, research should be conducted at a time when a substantial change in behavior is occurring, such as soon after the risk is recognized. If this is not possible, interventions that lead people to change their behavior (e.g., by raising risk perceptions or by lowering barriers to action) are required. In effect, they remove the system from equilibrium and allow one to watch what happens as people seek a new equilibrium. The least satisfactory choice is to use a cross-sectional correlation, such as R _H?B, that represents a summation over previous changes in behavior. The assumptions required to interpret such a correlation have been discussed earlier.     

A Review of: “Barkley,R. A., & Robin,A. L. (2008). Your Defiant Teen: 10 Steps to Resolve Conflict and Rebuild Your Relationship.”

We report a study that addressed behavior data recording by direct-care staff at a child services program. In response to a decreasing percentage of daily data recording in two community-based group homes, a supervisory intervention was implemented, consisting of a revised data recording form and providing performance feedback to the direct-care staff. The intervention increased and maintained the percentage of daily data recording each month across the two group homes and seven sets of child behavior data. The study represents one approach toward staff performance improvement within child services programs.     

Role Development

SUMMARY

In this chapter, I first explain my research stance, which reflects how I became interested in this study, as well as the personal perspective and professional background that I bring to the study, which may clarify how I may hear and listen to the participants and face biases that emerge (Ely et al., 1997; Tedlock, 1995; Van Manen, 1990). Next, I describe the research setting, the participants, and the methods for recruiting the participants. Finally, I outline the research procedures, data collection, data management, analysis, methods to achieve trustworthiness, presentation of the findings, negative analysis, and preparatory study.