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本文目的是介绍复杂抽样调查设计二值资料多重logistic回归分析方法。通过一个实例,利用八种不同的分析策略(不考虑抽样设计和抽样权重、考虑抽样设计不考虑抽样权重、不考虑抽样设计考虑抽样权重、同时考虑抽样设计和抽样权重以及分别不考虑与考虑派生变量)对数据进行建模。对所得结果进行比较得出如下结论:在对复杂抽样设计资料进行统计分析的过程中,同时考虑抽样设计和抽样权重可以得到符合数据内部变量间依赖关系真实情况的结论。此外,本研究还介绍了采用SAS软件中SURVEYLOGISTIC过程对复杂抽样调查数据进行多重Llogistic回归分析的详细步骤。 相似文献
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本文目的是介绍如何结合倾向性评分分析,合理地进行多重线性回归分析的方法。第一,介绍了与倾向性评分分析有关的3个基本概念。第二,介绍了倾向性评分分析的核心内容,即3种匹配方法。第三,通过一个流行病学的调查实例,介绍了如何用SAS软件进行分析的全过程,内容如下:①针对原始数据集,检验协变量在处理组与对照组之间的差异是否具有统计学意义;②针对原始数据集,直接进行多重线性回归分析;③采用倾向性评分分析产生匹配后的数据集;④针对匹配后的数据集,检验协变量在处理组与对照组之间的差异是否具有统计学意义;⑤针对匹配后的数据集,合理进行多重线性回归分析。 相似文献
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本文目的是介绍主成分回归分析的概念、作用以及用软件实现计算的方法。先对自变量进行主成分分析,然后将主成分变量视为新的自变量,再进行多重线性回归分析。通过不引入和引入派生变量以及采取不同的策略筛选自变量,可以获得多个合格的多重线性回归模型。在回归模型自由度接近相等时,基于残差方差最小、复相关系数最大为评价指标,从众多回归模型中优中选优。得出的经验为:应慎用主成分回归分析。 相似文献
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本文目的是介绍如何结合多水平模型分析,合理地进行多重Logistic回归分析的方法。第一,介绍了与多水平模型分析有关的4个基本概念。第二,介绍了构建多水平模型的3个步骤。第三,通过一个多中心药物临床试验的实例,介绍了如何用SAS软件进行分析的全过程,其内容如下:①检验各中心优势比之间是否具有齐性;②对试验中心产生哑变量后构建多重Logistic回归模型;③将试验中心视为分层变量构建多重Logistic回归模型;④构建随机截距多水平多重Logistic回归模型;⑤构建随机截距和随机斜率多水平多重Logistic回归模型。得到的结论是,当具有二值结果变量的各层级资料间存在差异时,最合适的做法是构建多水平多重Logistic回归模型。 相似文献
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本文目的是介绍基于经典统计思想实现多重线性回归分析的方法。首先,概述基于经典统计思想、贝叶斯统计思想和机器学习统计思想建立多重线性回归模型的基本思路;然后以实际问题为例,全面呈现了多重线性回归分析所需要完成的主要任务;最后,总结多重线性回归分析的适用场合及注意事项。结果表明:产生派生变量、进行自变量筛选和共线性诊断、进行异常点诊断等内容是进行多重线性回归分析的主要任务。在多因素试验或观察性研究中,只要结果变量为计量变量,比较常用且有效的做法是进行多重线性回归分析,应尽可能少用单因素差异性分析。 相似文献
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In the rat, brain growth is most vulnerable to undernutrition during the suckling period. Undernutrition at that stage also produces lasting effects on behaviour and it is often assumed that these are due to disturbances of brain growth. The proposal that this may not necessarily be so was explored by testing the behaviour of rats which had been undernourished at later stages of life and which, therefore, would be expected to show little or no deficit in brain growth. Rats were undernourished either immediately after weaning (25–67 days) or in adulthood (80–134 days) and were tested 3–4 months later on variable interval and variable ratio schedules of reinforcement with food as the reward. Their behaviour on these schedules was similar to that of rats undernourished during the suckling period: both groups responded or tended to respond at a higher rate than controls. Hence, it is possible that undernutrition at any stage in life may make animals more responsive to food when deprived subsequently. A cognitive mechanism for this change in behaviour is suggested. 相似文献
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不同性别惊恐障碍患者的临床变量比较 总被引:3,自引:0,他引:3
目的 旨在了解惊恐障碍患者的临床变量与性别差异。方法 对连续来门诊的54例男性和46例女性惊恐障碍患者的临床变量进行了对照比较。结果 在大学文化程度、结婚与否、家庭压力等变量方面,存在显著的性别差异(P〈0.05)。结论 提示已婚女性,在面临家庭压力时,易患惊恐障碍。 相似文献
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BACKGROUND:Studies have shown that monoclonal or polyclonal antibody injections of amyloid β peptide are effective in removing amyloid β peptide overload in the brain. OBJECTIVE: Based on successful screening of a human single-chain fragment variable antibody specific to amyloidβpeptide, this paper aimed to express recombinant human single-chain variable antibody against amyloid β peptide. DESIGN, TIME AND SETTING: A single sample experiment was performed at the Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Hospital (Beijing, China) from January to July 2006. MATERIALS: Human single-chain fragment variable antibody gene against amyloid β peptide was screened from a human phage-display antibody library. METHODS: Human single-chain fragment variable antibody gene was mutated to eliminate a BamHI restriction site and cloned into a T easy plasmid for pT-scFvAβ construction, which was identified by PCR amplification and endonuclease digestion. Plasmid pT-scFvAβ was cut by EcoRI and NotI endonucleases, and the antibody gene was cloned into pPIC9K plasmid to construct pPIC9K-scFvAβ expression vector, which was confirmed by gene sequencing. Linearized pPIC9K-scFvAβ was used to transform a Pichia pastoris GS115 cell line, and the recombinant was induced by 0.5% methanol to express human single-chain fragment variable antibody specific to amyloid β peptide. MAIN OUTCOME MEASURES: Protein electrophoresis was used to identify PCR products, gene sequencing was used to verify the pPIC9K-scFvA sequence, and SDS-PAGE was used to detect recombinant expression of human single-chain fragment variable antibody specific to amyloid β peptide in Pichia pastoris. RESULTS: Gene sequencing confirmed pPIC9K-scFvAβ orientation. Recombinants were obtained by linearized pPIC9K-scFvAβ transformation. After induction with 0.5% methanol, the recombinant yeast cells secreted proteins of 33-ku size. CONCLUSION: The expression vector pP 相似文献
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Jeon-Slaughter H Tucker P Pfefferbaum B North CS de Andrade BB Neas B 《Psychiatry and clinical neurosciences》2011,65(5):451-458
Aims: This study demonstrates that auxiliary and exclusion criteria variables increase the effectiveness of missing imputation in correcting underestimation of physiologic reactivity in relation to post‐traumatic stress disorder (PTSD) caused by deleting cases with missing physiologic data. Methods: This study used data from survivors of the 1995 Oklahoma City bombing and imputed missing heart rate data using auxiliary and exclusion criteria variables. Logistic regression was used to examine heart rate reactivity in relation to current PTSD. Results: Of 113 survivors who participated in the bombing study's 7‐year follow‐up interview, 42 (37%) had missing data on heart rate reactivity due to exclusion criteria (medical illness or use of cardiovascular or psychotropic medications) or non‐participation. Logistic regression results based on imputed heart rate data using exclusion criteria and auxiliary (the presence of any current PTSD arousal symptoms) variables showed that survivors with current bombing‐related PTSD had significantly higher heart rates at baseline and recovered more slowly back to baseline heart rate during resting periods than survivors without current PTSD, while results based on complete cases failed to show significant correlations between current PTSD and heart rates at any assessment points. Conclusions: Suggested methods yielded an otherwise undetectable link between physiology and current PTSD. 相似文献
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本文目的是介绍第一种提高回归模型拟合优度的策略,即哑变量变换与其他变量变换。具体方法包括以下几个方面:①对多值名义自变量采取"哑变量变换";②对定量和有序自变量引入派生变量,包括"对数变换""平方根变换""指数变换""平方变换""立方变换"和"交叉乘积变换"的结果;③对定量因变量分别采取"对数变换""平方根变换""指数变换""倒数变换"和"Logistic变换";④构建回归模型时,在假定"包含截距项"与"不含截距项"的条件下,分别采取"前进法""后退法"和"逐步法"筛选自变量。得到了如下几个结论:①对定量因变量和自变量不做变量变换时,回归模型的拟合优度非常差;②根据资料所具备的条件,对定量因变量采取不同的变量变换方法,其回归模型的拟合优度是不尽相同的;③对多值名义自变量进行"哑变量变换"是常规的做法,但存在不足之处;④对定量自变量引入派生变量是非常有价值的;⑤假定回归模型中不含截距项有助于提高回归模型的拟合优度。 相似文献
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目的 报道1例出现肌肥大和肌强直的普通变异型免疫缺陷(common variable immunodeficiency,CVID)伴随炎性肌肉病患者.方法 患者男性,33岁,近10年反复出现呼吸道感染症状,出现四肢无力和肌肉强直2年,伴随胸锁乳突肌和胫前肌肥大.对患者进行实验室检查,肌电图以及肌肉超声检查,并行股四头肌活体组织检查,标本进行组织学和标记炎细胞的免疫组织化学染色,以及强直性肌营养不良1型的萎缩性肌强直蛋白激酶基因的CTG重复次数和2型锌指蛋白9基因的CCTG重复次数的基因检查.结果 肌电图检查示强直电位和肌源性损害,肌肉超声提示肌肉肥大,肺活体组织检查提示炎性改变.辅助检查示贫血、尿蛋白阳性和血免疫球蛋白IgG、IgA和IgM均降低.肌肉活体组织检查可见肌纤维坏死和再生,伴随间质增生和大量炎细胞浸润.浸润的炎细胞主要是巨噬细胞和T淋巴细胞.存在主要组织相容性复合物Ⅰ阳性肌纤维.强直性肌营养不良1型和2型的基因检查正常.结论 CVID伴随的炎性肌肉病可以出现肌强直和肌肥大表现. 相似文献
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We report a patient with common variable immunodeficiency (CVID) who developed an axonal sensorimotor polyneuropathy, a hitherto unreported association to our knowledge. These conditions may be linked at the pathogenetic level, since some CVID patients are prone to the development of autoimmune disease. 相似文献