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1.
采用多元类比方法,对多元函数的概念、极限、分析性质与一元函数的相应内容进行比较,分析,揭示两者中的"形同实异"及"形异实同",按照系统论原则,从多元函数极限概念的内部结构与外部联系,从它的概念的形成与发展的来龙去脉加以认识,用系统化的方法做出全面的分析,对有效的理解和掌握多元函数极限及微分学起到重要作用。在此基础上给出求多元函数极限相应的教学策略。 相似文献
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判别分析是多元统计分析的一种方法,已在物种分类、经济分析、地质勘探、天气预报等诸多领域得到广泛的应用。本文首先介绍了判别分析的数学模型和求解方法,然后结合第十次新增博士学位授予单位的实际评审材料,阐述了判别分析方法在此类评估中的应用,以期该定量分析方法能在教育评估领域得到有效的利用。 相似文献
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OBJECTIVE: It has been suggested that survivors of ongoing childhood sexual abuse (CSA) tend to have been reared in ineffective family environments that render them particularly vulnerable to maltreatment and which foster psychological difficulties beyond those accounted for solely by their abuse. If this conjecture is valid, one would expect that the family of origin environments of CSA survivors would be disturbed whether their abuser was intra-familial or extra-familial. To assess this hypothesis, two studies compared the childhood family of origin environments and supportive parenting characteristics of a clinical sample of women sexually abused by family members only (the intra-familial group), by non-family members only (the extra-familial group), and by both family and non-family members (the "both" group). METHOD: Study 1 compared the three groups (total N = 213) using the Family Environment Scale (FES). Study 2 compared groups (total N = 86) on the positive parenting scales of the Exposure to Abusive and Supportive Environments Parenting Inventory (EASE-PI). RESULTS: In Study 1, multivariate analyses indicated significant differences on the independence, cohesion, and conflict subscales of the FES. Pairwise comparisons revealed that the extra-familial group reported significantly higher levels of family independence and lower levels of conflict than the other two groups. In addition, the extra-familial group reported higher levels of cohesion than the intra-familial group. However, the effect sizes of these comparisons were extremely small. In Study 2, multivariate analyses revealed no group differences on the EASE-PI scales. CONCLUSIONS: Low effect sizes on the three significant FES scales, non-significance on the remaining seven FES scales, and non-significance on the EASE-PI scales suggest that there is considerable similarity in the family of origin environments of adult female CSA survivors seeking therapy regardless of whether their perpetrators were family members, non-family members, or both family and non-family members. 相似文献
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Robert A. Horn Corinna A. Ethington 《Community College Journal of Research & Practice》2013,37(5):401-413
This study examined whether community college students of differing ethnic backgrounds and enrollment status differed in their perceptions of their growth and development gains as a function of their college experience. The sample consisted of four ethnic groups intending to transfer to four-year institutions. Four gain scales were created to operationalize the student's perceptions of gains. The multivariate test for the interaction of ethnic group and enrollment status was nonsignificant; differences in perceived growth among ethnic groups did not depend on their enrollment status. Significant main effects were found in differences among ethnic groups and between full-time and part-time students. 相似文献
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The local characteristics of multi-dimensional random variables are seldom considered in the general modeling method of multivariate copula.A new modeling method,called pair-copula construction,is introduced to remedy this defect.Different types of copula distribution functions are allowed to be introduced in this method.Correspondingly,the related characteristics of complex multivariate can be described by a cascade of pair-copula acting on two variables at a time.In the analysis of asynchronism-synchronism of regional precipitation in WED interbasin water transfer areas,the pair-copula construction method is compared with the general modeling method of multivariate copula.The results show that the local dependence structure would exist among hydrologic variables even in three-dimensional cases.In this situation,the general modeling method of multivariate copula would face difficulties in fitting distribution.However,the pair-copula construction method could capture the local information of hydrologic variables efficiently by introducing different types of copula distribution functions.Moreover,the compensation capacity of water resources is strong in different hydrological areas of WED water transfer project.The asynchronous frequency of wetness and dryness is 69.64% and the favorable frequency for water transfer is 46.15%. 相似文献
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葡萄与葡萄酒质量的综合评价 总被引：1，自引：0，他引：1
从体现酒品质量的感官评价和酿酒葡萄与葡萄酒的理化指标两方面入手,运用t检验、主成分分析法、模糊c均值聚类分析、多元线性回归分别建立显著性差异检验、主成分、聚类分析、质量影响和论证等模型,并运用SPSS、Matlab7软件,得出两组评酒员的评价结果差异性和可信度,酿酒葡萄的分级,酿酒葡萄与葡萄酒的理化指标之间的联系,最后分析并论证了葡萄、葡萄酒的理化指标与葡萄酒质量的关系. 相似文献
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Jeffrey P. Dorman 《Educational Research and Evaluation》2013,19(5):429-444
This paper reports the reanalysis of data collected in a study of 3 determinants of classroom environment (viz. year level, subject, and school type) using multivariate analysis of variance and multilevel analysis. Data were collected from 2,211 students in Queensland Catholic and government schools. The Catholic School Classroom Environment Questionnaire, which assesses student affiliation, interactions, cooperation, task orientation, order and organisation, individualisation, and teacher control, was administered to the sample. The original multivariate analyses which used the class as the unit of analysis were supplemented by similar analyses using the student as the unit of analysis and multilevel analyses. While multilevel analyses yielded tests of significance results similar to multivariate analyses conducted with the class as the unit of analysis, effect sizes for the multilevel analyses were similar to those reported for multivariate tests conducted with the student as the unit of analysis. 相似文献
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本文利用模糊聚类分析方法，对青海省六个主要民族18岁女学生体质健康进行了综合评价，得到基本分类：汉、土、蒙古族女学生为一类，回、撒拉族女学生为一类，藏族女学生自成一类．为有关部门今后有针对性地增强学生体质，指导她们科学锻炼身体提供了依据． 相似文献
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给出对应于多元多重正交尺度函数的多重小波包的定义及其构造方法,讨论了多元多重不可分正交小波包的性质。 相似文献
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针对各学科领域中常遇到的多元线性回归问题,在简单介绍回归分析基本理论的基础上,结合一具体实例,详细介绍了基于回归算法编写MATLAB程序、利用MATLAB预定义函数以及二者相结合解决多元线性回归问题的方法。方法简单实用,其中基于算法编程、利用预定义函数及二者结合解决问题的方法不仅是解决多元线性回归问题的方法,也是利用MATLAB解决各学科领域中一般性数学问题的基本方法。 相似文献
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李敏 《黑龙江教育学院学报》2012,(11):83-84
采用MRQ问卷随机调查了300名小学生,取得了小学生阅读倾向的原始数据。随后利用多元统计方法处理调查数据,得出影响小学生阅读动机的六个因子,根据这六个因子,将小学生阅读分成分享型、上进型、任务型、放松型、自我型、迷茫型六个类别。 相似文献
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彭明珠 《北京城市学院学报》2002,(1):79-82
多元函数极值是微积分课程的一个重要概念 ,文章通过定义并结合具体实例将极值和弱极值概念作一对比 ,以说明它们的区别。同时还指出了条件极值和无条件极值在概念上及求法上的一些区别 相似文献
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The latent growth model (LGM) in structural equation modeling (SEM) may be extended to allow for the modeling of associations among multiple latent growth trajectories, resulting in a multiple domain latent growth model (MDLGM). While the MDLGM is conceived as a more powerful multivariate analysis technique, the examination of its methodological performance is very limited. Hence, the present study compared the power of the MDLGM with that of a set of univariate LGMs for detecting group differences in growth rates over time using a Monte Carlo study with a two-group and two-domain design. The results indicated that there were different scenarios where the power rates for the MDLGM were greater than that of the set of LGMs (and vice versa) due to a joint function of the two domains’ intercorrelation size and the group difference effect size. 相似文献
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马田系统是一种新的模式识别技术,这种技术的主要思想是通过构造一多维基准测量空间对多维数据资料进行诊断与预测。通过对马田系统基本原理的研究,将其应用于Fisher关于鸢尾花类型的判别问题,结果表明,MTS方法具有良好的判别效果。 相似文献
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Kim De Roover Jeroen K. Vermunt Marieke E. Timmerman Eva Ceulemans 《Structural equation modeling》2017,24(4):506-523
Given multivariate data, many research questions pertain to the covariance structure: whether and how the variables (e.g., personality measures) covary. Exploratory factor analysis (EFA) is often used to look for latent variables that might explain the covariances among variables; for example, the Big Five personality structure. In the case of multilevel data, one might wonder whether or not the same covariance (factor) structure holds for each so-called data block (containing data of 1 higher level unit). For instance, is the Big Five personality structure found in each country or do cross-cultural differences exist? The well-known multigroup EFA framework falls short in answering such questions, especially for numerous groups or blocks. We introduce mixture simultaneous factor analysis (MSFA), performing a mixture model clustering of data blocks, based on their factor structure. A simulation study shows excellent results with respect to parameter recovery and an empirical example is included to illustrate the value of MSFA. 相似文献
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Females are known to excel over males in most reading tasks, but notconsistently so in tasks that require processing information from maps,tables, charts and diagrams, so called `Documents'. The IEA ReadingLiteracy data provides possibilities to investigate gender differencesacross countries in such tasks in two age groups, 9-year-olds and14-year-olds. The general question about cultural influences vs. aninvariant pattern of gender differences is of great interest for genderresearch, and central in this study. The aim of the paper is to describeand analyze gender differences on Document tasks, and investigate if andhow the pattern of differences varies over countries. Another aim is todemonstrate the power of using a multivariate analysis technique bycontrasting it against traditional univariate approaches. The univariateanalysis indicates female advantage as the most common in the youngergroup and a mixed pattern in the older. The multivariate analysisindicate that Document tasks are not unidimensional, because bothgeneral and specific dimensions can be extracted from the raw scores.The traditional univariate analysis often disguised true patterns ofdifferences in the data, both in terms of country differences and interms of the direction of the gender differences. Raw score differencesbetween the genders proved to be due to differences in both general andpassage specific dimensions. Ten of the countries showed genderdifferences in both directions in the general dimension among9-year-olds, while an almost consistent pattern of female advantage wasfound among 14-years-olds. Many of the specific passage dimensionsturned out to favor either males or females. This complex pattern variedover both age groups and across countries, although commonalities in thepattern among subgroups of countries were common. 相似文献
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Jacob Yuichung Chan Annis L. Fung Lawrence H. Gerstein 《Psychology in the schools》2013,50(2):181-192
Research on aggression in the West has focused mainly on the dichotomy between proactive and reactive aggression, but not the co‐occurring proactive–reactive aggression subtype, despite its prevalence. The authors investigated the differences in psychological and behavioral correlates among proactive, reactive, and proactive–reactive student aggressors and nonaggressors in Hong Kong, China, based on their scores on the Reactive and Proactive Aggression Questionnaire. Participants were 1,356 secondary school students (805 males and 551 females, aged 11 to 18 years). A one‐way multivariate analysis of covariance was conducted to examine group differences in aggression, attention deficits, anxiety/depression, and delinquency. Results showed that proactive–reactive aggressors were significantly more aggressive, less attentive, more anxious/depressed, and more engaged in delinquent behaviors. Reactive and proactive aggressors did not differ in three of these four behaviors. Implications for research and practice when working with proactive–reactive aggressors are discussed. 相似文献
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Reinoud D. Stoel Thea T. D. Peetsma Jaap Roeleveld 《Learning and individual differences》2001,13(4):345
Latent growth curve (LGC) analysis of longitudinal data for pupils' school investment, self-confidence and language ability is presented. A multivariate model is tested that relates the three developmental processes to each other and to intelligence. All processes show significant differences between children in their developmental curves. The increase in language ability and the decrease in school investment correspond with the hypotheses. No hypothesis is formulated about self-confidence, but an increase for some and a decrease for others are found. The hypothesis that development in language ability, school investment, and self-confidence are mutually positively associated is supported, as is the hypothesis that intelligence accounts for some of the differences in language ability. School investment, self-confidence, and intelligence each explain a different part of development in language ability. 相似文献
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This study explores differences in the job status, stability, and satisfaction of recent four-year college graduates with varying lengths of attendance at two-year institutions. A longitudinal design with controls for salient pre-college characteristics is employed. Results of the multivariate analysis of covariance indicate no differences in the early career outcome measures between students whose undergraduate preparation was solely in four-year colleges and those whose preparation was at both two- and four-year colleges. The administrative and research implications of these results are discussed. 相似文献