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41.
Often quantitative data in the social sciences have only ordinal justification. Problems of interpretation can arise when least squares multiple regression (LSMR) is used with ordinal data. Two ordinal alternatives are discussed, dominance-based ordinal multiple regression (DOMR) and proportional odds multiple regression. The Q2 statistic is introduced for testing the omnibus null hypothesis in DOMR. A simulation study is discussed that examines the actual Type I error rate and power of Q2 in comparison to the LSMR omnibus F test under normality and non-normality. Results suggest that Q2 has favorable sampling properties as long as the sample size-to-predictors ratio is not too small, and Q2 can be a good alternative to the omnibus F test when the response variable is non-normal. 相似文献
42.
Present optimization techniques in latent class analysis apply the expectation maximization algorithm or the Newton-Raphson
algorithm for optimizing the parameter values of a prespecified model. These techniques can be used to find maximum likelihood
estimates of the parameters, given the specified structure of the model, which is defined by the number of classes and, possibly,
fixation and equality constraints. The model structure is usually chosen on theoretical grounds. A large variety of structurally
different latent class models can be compared using goodness-of-fit indices of the chi-square family, Akaike’s information
criterion, the Bayesian information criterion, and various other statistics. However, finding the optimal structure for a
given goodness-of-fit index often requires a lengthy search in which all kinds of model structures are tested. Moreover, solutions
may depend on the choice of initial values for the parameters. This article presents a new method by which one can simultaneously
infer the model structure from the data and optimize the parameter values. The method consists of a genetic algorithm in which
any goodness-of-fit index can be used as a fitness criterion. In a number of test cases in which data sets from the literature
were used, it is shown that this method provides models that fit equally well as or better than the models suggested in the
original articles. 相似文献
43.
Nicholas Long Barbara-Jeanne Austin Mary M. Gound Abesie O. Kelly Adrienne A. Gardner Rick Dunn Stacy B. Harris Kim S. Miller 《Journal of child and family studies》2004,13(1):47-65
The Parents Matter! Program (PMP) has developed three interventions for parents of 4th and 5th grade African-American children (9–12 years old). The overarching goal of all three interventions is to provide parents with knowledge, skills, and support for enhancing their efforts to raise healthy children. The interventions are: (1) Enhanced Communication and Parenting (five 2
-hour sessions), (2) Brief Communication and Parenting (single 2
-hour session), and (3) General Health (single 2
-hour session). This article discusses the development of these interventions, presents an overview of the content of each intervention, and discusses issues related to the facilitation/presentation of these interventions. 相似文献
44.
Analysis of accuracy of responses to balance scale problems gives a global idea of the cognitive processes that underlie problem-solving behavior on this task. We show that response times (RTs) provide additional detailed information about the kind and duration of these processes. We derive predictions about the RTs from Siegler's (1981) model for the balance scale task, including the counterintuitive prediction that young adults are slower than children in solving particular balance scale problems. The predictions were tested in a study in which 191 6- to 22-year-old participants were presented with a computerized balance scale task. RTs were analyzed with regression models. In addition to qualitative differences between items, we also modeled quantitative differences between items in the regression models. Analyses supported the predictions and provided additional knowledge on the rules. Rule II was reformulated as a rule that always involves the encoding, but not always the correct application of the distance cue. RTs provided evidence for the use of a buggy-rule and not an addition-rule. Finally, a relation between rule inconsistency and increased RT was found. 相似文献
45.
Solitude may be positive or negative, depending on situational and personal factors. From prior research, nine types of solitude were identified. Based on data from a questionnaire study of undergraduate participants, factor analysis suggests that these nine types can be reduced to three dimensions, two positive and one negative. These are, respectively, Inner-Directed Solitude (characterized by self-discovery and inner peace), Outer-Directed Solitude (characterized by intimacy and spirituality), and Loneliness. Personality and value correlates, as well as situational correlates, of the various types of solitude also were explored. 相似文献
46.
47.
韩维举 《医学与哲学(人文社会医学版)》1999,20(3):19-21
耳科学在人类与耳部疾病的斗争中兴起了19世纪,在本世纪随科学技术的发展而获得迅速发展,特别是抗菌素和手术显微镜的出现,使耳显同外科技术不断提高,不仅能彻底地祛除耳部感染,而且可以有效地提高听力,耳科学家在聋病的治疗过程中,已能够有效地治疗传导性耳聋,但仍面临着治疗神经性耳聋的挑战,在现代科学技术革命的推动下,随着分析子生物学,细胞生物学等新技术的发展,在21世纪,人类必定能够彻底治疗聋病。 相似文献
48.
论中西医结合的过程与层次 总被引:2,自引:0,他引:2
韩乾国 《医学与哲学(人文社会医学版)》1999,20(6):12-15
中西医结合是一个长期困扰人们的难题。中医理论研究人体外部现象的变化规律,以古代哲学思想为指导,具有整体联系、动态把握的合理内核。而目前现代医学对人体结构和功能的认识,并不能完全揭示生命现象本质,因而也不能完全解释中医现象。这种认识有一个不断发展和深化的过程,自然辩证法观点认为层次越低、结合越紧密。分子导次是具有生物意义的最低层次。人类“基因组”计划的实现可能在一个新的高度阐明人体本质,也使中医现象 相似文献
49.
Aimée M. Surprenant Susan L. Hura Mary P. Harper Leah H. Jamieson Glenis Long Scott M. Thede Ayasakanta Rout Tsung-Hsiang Hsueh Stephen A. Hockema Michael T. Johnson Pramila N. Srinivasan Christopher M. White J. Brandon Laflen 《Behavior research methods》1999,31(4):638-649
Ratings of familiarity and pronounceability were obtained from a random sample of 199 surnames (selected from over 80,000 entries in the Purdue University phone book) and 199 nouns (from the Ku?era-Francis, 1967, word database). The distributions of ratings for nouns versus names are substantially different: Nouns were rated as more familiar and easier to pronounce than surnames. Frequency and familiarity were more closely related in the proper name pool than the word pool, although both correlations were modest. Ratings of familiarity and pronounceability were highly related for both groups. A production experiment showed that rated pronounceability was highly related to the time taken to produce a name. These data confirm the common belief that there are differences in the statistical and distributional properties of words as compared to proper names. The value of using frequency and the ratings of familiarity and pronounceability for predicting variations in actual pronunciations of words and names are discussed. 相似文献
50.
汉字词识别过程的形,音,义编码作用的研究 总被引:7,自引:0,他引:7
本文通过两个实验,采用汉字词形、音、义特征匹配任务,探讨了影响汉字词的形、音、义编码与提取方式的有关因素。实验一发现在速示条件下,对汉字词再认的成绩并不受字词的使用度的影响,反应时无明显变化,而主要受编码加工的深度影响。在形、音、义特征加工中,对音码的加工时间最长,再认的正确率最低;义码的加工时间较短,再认正确率最高;形码的反应时及再认成绩介于音码与义码之间。实验二在非速示条件下也获得了相同的结果。研究结果表明,在汉字词的形、音、义特征中,存在着编码加工深度的差异。 相似文献