A Comparison Of Ordinary Least Squares, Weighted Least Squares, And Other Procedures When Testing For The Equality Of Regression

When testing for the equality of regression slopes based on ordinary least squares (OLS) estimation, extant research has shown that the standard F performs poorly when the critical assumption of homoscedasticity is violated, resulting in increased Type I error rates and reduced statistical power (Box, 1954; DeShon & Alexander, 1996; Wilcox, 1997). Overton (2001) recommended weighted least squares estimation, demonstrating that it outperformed OLS and performed comparably to various statistical approximations. However, Overton\u27s method was limited to two groups. In this study, a generalization of Overton\u27s method is described. Then, using a Monte Carlo simulation, its performance was compared to three alternative weight estimators and three other methods. The results suggest that the generalization provides power levels comparable to the other methods without sacrificing control of Type I error rates. Moreover, in contrast to the statistical approximations, the generalization (a) is computationally simple, (b) can be conducted in commonly available statistical software, and (c) permits post hoc analyses. Various unique findings are discussed. In addition, implications for theory and practice in psychology and future research directions are discussed

On the Conditional and Unconditional Type I Error Rates and Power of Tests in Linear Models with Heteroscedastic Errors

Preliminary tests for homoscedasticity may be unnecessary in general linear models. Based on Monte Carlo simulations, results suggest that when testing for differences between independent slopes, the unconditional use of weighted least squares regression and HC4 regression performed the best across a wide range of conditions

Computerized Dynamic Visual Tests For Workplace Applications: Effects Of Age And Subsidiary Issues

Workplace tasks require the processing of visual information and some are so dependent on vision that tests for task dependent visual capabilities are often used to screen job applicants. While visual acuity is still currently seen as the most important ability for the processing of visual information, other capabilities have also been recognized as important. A complete assessment of visual processing now entails, in addition to visual acuity, measures of contrast sensitivity, visual fields, scotopic and photopic sensitivity, depth perception, color vision, and eye muscle balance. Generally, these measures involve the use of stationary stimuli presented for a period of time and under static conditions. However, visual information processing in many workplace tasks involves the rapid presentation of visual images which change over time. © 2005 Elsevier B.V. All rights reserved

A User-Centered Design Exploration of Factors That Influence the Rideshare Experience

The rise of real-time information communication through smartphones and wireless networks enabled the growth of ridesharing services. While personal rideshare services (individuals riding alone or with acquaintances) initially dominated the market, the popularity of pooled ridesharing (individuals sharing rides with people they do not know) has grown globally. However, pooled ridesharing remains less common in the U.S., where personal vehicle usage is still the norm. Vehicle design and rideshare services may need to be tailored to user preferences to increase pooled rideshare adoption. Based on a large, national U.S. survey (N = 5385), the results of exploratory and confirmatory factor analyses suggested that four key factors influence riders’ willingness to consider pooled ridesharing: comfort/ease of use, convenience, vehicle technology/accessibility, and passenger safety. A binomial logistic regression was conducted to determine how the four factors influence one’s willingness to consider pooled ridesharing. The two factors that positively influence riders’ willingness to consider pooled ridesharing are vehicle technology/accessibility (B = 1.10) and convenience (B = 0.94), while lack of passenger safety (B = −0.63) and comfort/ease of use (B = −0.17) are pooled ridesharing deterrents. Understanding user-centered design and service factors are critical to increase the use of pooled ridesharing services in the future

A Comparison Of Face-To-Face And Electronic Peer-Mentoring: Interactions With Mentor Gender

The present study compared the relative impact of peer-mentoring that took place either face-to-face or through electronic chat. Protégés were 106 college freshmen randomly assigned to a senior college student mentor and to one of the two communication modes. Fifty-one mentors interacted with one of these proteges face-to-face and one solely through electronic chat. Electronic chat resulted in less psychosocial support, career support, and post-mentoring protege self-efficacy for those with male but not female mentors. Analyses of coded transcripts revealed that males condensed their language to a greater extent than did females in the electronic chat condition relative to the face-to-face condition. Dyads in the electronic chat condition had more interactive dialogue than did those in the face-to-face condition. Finally, dialogue interactivity predicted post-mentoring self-efficacy but only for those who communicated through electronic chat. © 2007 Elsevier Inc. All rights reserved

On the Conditional and Unconditional Type I Error Rates and Power of Tests in Linear Models with Heteroscedastic Errors

Preliminary tests for homoscedasticity may be unnecessary in general linear models. Based on Monte Carlo simulations, results suggest that when testing for differences between independent slopes, the unconditional use of weighted least squares regression and HC4 regression performed the best across a wide range of conditions