Two-Level Dynamic Structural Equation Models with Small Samples

Advances in data collection have made intensive longitudinal data easier to collect, unlocking potential for methodological innovations to model such data. Dynamic structural equation modeling (DSEM) is one such methodology but recent studies have suggested that its small N performance is poor. This is problematic because small N data are omnipresent in empirical applications due to logistical and financial concerns associated with gathering many measurements on many people. In this paper, we discuss how previous studies considering small samples have focused on Bayesian methods with diffuse priors. The small sample literature has shown that diffuse priors may cause problems because they become unintentionally informative. Instead, we outline how researchers can create weakly informative admissible-range-restricted priors, even in the absence of previous studies. A simulation study shows that metrics like relative bias and non-null detection rates with these admissible-range-restricted priors improve small N properties of DSEM compared to diffuse priors.     

On Fitting a Multivariate Two-Part Latent Growth Model

The purpose of this study was to explore the influence of the number of targets specified on the quality of exploratory factor analysis solutions with a complex underlying structure and incomplete substantive measurement theory. Three Monte Carlo studies were performed based on the ratio of the number of observed variables to the number of underlying factors. Within each study, communality, sample size, and the number of targets were manipulated. Outcomes included a measure of congruence and a measure of variability with regard to the rotated pattern matrix. The magnitude of the main effect for the influence of the number of targets on congruence and variability ranged from moderate to large. The magnitude of the interaction between the number of targets and level of communality ranged from small to moderate with regard to congruence and variability. Consistent with theoretical expectations, the minimum number of targets to specify to be reasonably assured of obtaining an accurate solution varied across study conditions.     

Graphical Extension of Sample Size Planning With AIPE on RMSEA Using R

Kelley and Lai (2011) recently proposed the use of accuracy in parameter estimation (AIPE) for sample size planning in structural equation modeling. The sample size that reaches the desired width for the confidence interval of root mean square error of approximation (RMSEA) is suggested. This study proposes a graphical extension with the AIPE approach, abbreviated as GAIPE, on RMSEA to facilitate sample size planning in structural equation modeling. GAIPE simultaneously displays the expected width of a confidence interval of RMSEA, the necessary sample size to reach the desired width, and the RMSEA values covered in the confidence interval. Power analysis for hypothesis tests related to RMSEA can also be integrated into the GAIPE framework to allow for a concurrent consideration of accuracy in estimation and statistical power to plan sample sizes. A package written in R has been developed to implement GAIPE. Examples and instructions for using the GAIPE package are presented to help readers make use of this flexible framework. With the capacity of incorporating information on accuracy in RMSEA estimation, values of RMSEA, and power for hypothesis testing on RMSEA in a single graphical representation, the GAIPE extension offers an informative and practical approach for sample size planning in structural equation modeling.     

硫氰酸亚铜产品纯度的测定

分别采用佛尔哈德返滴定法和间接碘量法测定了由废液制得硫氰酸亚铜产品中硫氰酸根和总铜的含量。硫氰酸根的待测试液由样品与NaOH溶液通过加热反应制备;测定总铜的试液分别采用硫酸—硝酸和过氧化氢—硝酸与样品反应制备,实验结果表明,用两种方法制备铜试液所测得的总铜含量无差异。所提出的用过氧化氢—硝酸制备总铜试液的方法较硫酸—硝酸制备方法具有方便、快捷的优点。     

选词批评与词法示范——论许昂霄的《晴雪雅词》、《词综偶评》

清代词选多为专业词家编纂,手眼甚高,在选本的功用上,往往侧重于推尊词体、开宗立派,而于示人词法方面则略有忽视.许昂霄坐馆于涉园张氏,因指导张氏子弟填词之需,编选《晴雪雅词》,评点《词综》,偏重于词法的讨论与示范.另外,《词综偶评》、《晴雪雅词》的选词理念和批评主张,对浙派思想既有继承,又有所批判,提出尚自然,贵性情等创作思想,来纠正浙西词派的偏至,一定意义上弥补了浙派的若干不足.     

汉语声母韵母习得问题研究

从汉语普通话的发音规律及特点,探讨母语背景为法语的学生在学习普通话声母韵母时的难点及问题,分析问题产生的原因并由此提出对法学习上的建议,希望能为法语背景的汉语学习者提供新的学习思路。     

如何制定小学语文单元知识网络图

制定单元知识网络图,旨在明确每个单元、每篇课例“教什么”“学什么”的内容,尝试“怎么教”“怎么学”的有效方法,以其提高教学质量。     

图书丢失率调查方案的设计与实践

文章介绍江南大学图书馆以图书半衰期作为新旧书划分线而设计的一种调查图书丢失率的方案,并用加权数学公式对数据进行分析处理,指出新书丢失率的确认和控制将是图书馆馆藏管理的重点,并对方案的初步实践进行反思和总结,给出合理的图书丢失率的数值范围.     

“燃烧热测定”教学实验的改进

本文介绍了在燃烧热的测定实验中采用双孔带槽模底,单、双股燃烧丝相结合的挂样片法,代替单孔或无孔模底,单股燃烧丝接触样片法,以及压片操作技法。四年的实践表明,这种实验方法大大提高了实验的成功率,缩短了实验操作时间。     

CAN总线位速率参数在实际应用中设置的研究分析

CAN总线是一种有效支持分布式控制和实时控制的、多主的异步串行通信网络。CAN通信中的波特率、位周期内取样点数和位置的设置极大地影响了CAN性能的发挥。优化位定时参数,能够保证信息同步,并且对它设置的恰当与否关系着整个系统通信的成败。本文就是针对这点来说明位定时参数的确定方法及其重要性。