文本结构和时间应激对网页阅读绩效的影响

探讨了文本结构和时间应激对网页阅读绩效的影响效应。采用 2× 3被试间设计 ,自变量为文本结构和阅读时间 ,因变量为找到相关信息的时间及途径的额外节点数。结果发现 ,主效应及交互作用的影响均十分显著。其中 ,当阅读时间为 10和 2 0min时 ,超文本阅读的绩效均显著低于线性文本 ,而在 30min时两者无显著差异 ;对超文本 ,三种阅读时间的效应存在显著差异 ,而对线性材料 ,阅读时间的效应无显著差异。结论 :时间应激对超文本阅读绩效的影响更为明显     

Reasonable reasons for waiting

Recent decision‐making research claims to establish that, in violation of Savage's normative sure‐thing principle, individuals often wait to acquire noninstrumental information and subsequently base their decisions upon this information. The current research suggests that characterizing individuals as pursuing noninstrumental or useless information may be overstated. Through a series of experiments we establish, first, that many people choose to wait, even when waiting provides no additional information at all. Second, the longer people are allowed to wait before having to decide, the more people prefer to wait rather than decide immediately. Third, those individuals who choose to wait are the ones less confident about committing themselves to a decision. For them, the benefit from waiting may be especially valuable by allowing them to come to terms with a less‐than‐ideal decision. Copyright © 2003 John Wiley & Sons, Ltd.     

Can we disregard the whole model? Omnibus non-inferiority testing for R2 in multi-variable linear regression and in ANOVA

Determining a lack of association between an outcome variable and a number of different explanatory variables is frequently necessary in order to disregard a proposed model (i.e., to confirm the lack of a meaningful association between an outcome and predictors). Despite this, the literature rarely offers information about, or technical recommendations concerning, the appropriate statistical methodology to be used to accomplish this task. This paper introduces non-inferiority tests for ANOVA and linear regression analyses, which correspond to the standard widely used F test for and R², respectively. A simulation study is conducted to examine the Type I error rates and statistical power of the tests, and a comparison is made with an alternative Bayesian testing approach. The results indicate that the proposed non-inferiority test is a potentially useful tool for ‘testing the null’.     

A Comparative Investigation of Confidence Intervals for IndependentVariables in Linear Regression

In linear regression, the most appropriate standardized effect size for individual independent variables having an arbitrary metric remains open to debate, despite researchers typically reporting a standardized regression coefficient. Alternative standardized measures include the semipartial correlation, the improvement in the squared multiple correlation, and the squared partial correlation. No arguments based on either theoretical or statistical grounds for preferring one of these standardized measures have been mounted in the literature. Using a Monte Carlo simulation, the performance of interval estimators for these effect-size measures was compared in a 5-way factorial design. Formal statistical design methods assessed both the accuracy and robustness of the four interval estimators. The coverage probability of a large-sample confidence interval for the semipartial correlation coefficient derived from Aloe and Becker was highly accurate and robust in 98% of instances. It was better in small samples than the Yuan-Chan large-sample confidence interval for a standardized regression coefficient. It was also consistently better than both a bootstrap confidence interval for the improvement in the squared multiple correlation and a noncentral interval for the squared partial correlation.     

Waiting for a kidney from a deceased donor: an interpretative phenomenological analysis

Demand for kidneys from deceased donors far outstrips supply. Despite this, there appears to be little research that focuses solely on the experience of waiting for a kidney from a deceased donor. This study uses the qualitative methodology interpretative phenomenological analysis to explore the lives of 10 people on the transplant list, with the aims of illuminating the potential psychological challenges those on the list may face during this time, and providing information to help clinicians more fully support such people in the future. Two themes connected to the experience of waiting – adjustment to the uncertainty of waiting and thinking about receiving a kidney from a living donor – are presented here. Participants describe a sense of confusion and uncertainty around life on the list, and discuss their strategies for dealing with this. Novel complexities around the ambiguous challenge of receiving an organ from a deceased donor are revealed. It is recommended that health care teams provide a forum for this patient group to work through these feelings of confusion and ambiguity.     

The stress of food allergy issues in daily life

Objective: Food allergies are a growing health concern, but their implications for daily psychological functioning are unknown. This micro-longitudinal study investigated the daily frequency of food allergy issues and how this related to experiences of stress, mood and physical energy.

Design: One hundred and eight adults with physician-diagnosed food allergies completed an initial Internet survey followed by a 2-week Internet daily diary survey.

Main outcome measures: The initial survey collected socio-demographic and food allergy information. The daily survey collected information about the participants’ experiences of stress, mood, physical energy and food allergy issues during that day.

Results: Commonly experienced allergy issues included negative physical symptoms, higher food prices, anxiety about safety of food, trouble maintaining a healthy diet and anxiety/stress at social occasions. Furthermore, multilevel modelling analyses showed that stress and negative mood were significantly higher on days with more allergy issues. Older adults experienced lower positive mood and physical energy on days with more issues.

Conclusion: This is the first study to incorporate near to real-time tracking to examine the frequency of food allergy issues and the implications for daily psychological functioning. Targeting the issues we identified could reduce stress in patients with food allergies and improve their overall quality of life.     

基于阶层线性理论的多层级中介效应

本文介绍了三种常见的多层级中介效应模型, 并根据阶层线性理论和依次检验回归系数的方法, 详述了多层级中介效应的检验步骤以及中介效应量的估计方法, 在2-1-1和1-1-1中介效应模型中, 推荐采用对层1自变量按组均值中心化, 同时将组均值置于层2截距方程式的中心化方法, 以实现组间和组内中介效应的有效分离。本文还展望了多层级中介效应模型的拓展方向, 即多层级调节性中介模型和多层级结构方程模型; 以及检验方法的拓展, 即Sobel检验和置信区间检验。     

Fourier‐Motzkin elimination method in MOLP problems

This paper introduces a method for finding the non‐dominated set in criterion space of an MOLP problem based on Fourier–Motzkin Elimination. The method incorporates a procedure that eliminates decision variables from constraints and transforms a feasible region from decision space to criterion space. While avoiding characterization of the efficient set in decision space, it finds the non‐dominated set in criterion space. After the decision maker's most preferred criterion vector has been identified, the corresponding efficient solutions can be found by backward substitution. The method was implemented in MATLAB using a tabular form and computational experiments were conducted. The results indicate that although the method performs well for relatively small problems, it can be computationally intensive for larger problems. Nonetheless, the method is intuitively appealing and it provides useful insights into the geometry and theory of MOLP. As such it makes it a valuable educational tool for students of multi‐criteria decision analysis. Copyright © 2003 John Wiley & Sons, Ltd.