Resampling probability values for differences between two independent indices of ordinal variation and consensus

A permutation method is presented to calculate resampling probability values for differences between two independent indices of ordinal variation and consensus.     

A measure of effect size for r x c contingency tables

Goodman and Kruskal's tau measure of categorical association is advanced as a replacement for conventional measures of effect size for r x c contingency tables. Goodman and Kruskal's tau is an asymmetric measure of categorical association which is based entirely on the observed data and possesses a clear interpretation in terms of proportional reduction in error. Comparisons with conventional measures of effect size based on chi-squared such as Pearson's phi2, Tschuprow's T2, and Cramer's V2 demonstrate the advantages of employing tau as a measure of effect size.     

The dimensions of stage theories

Stage theories are commonly used to represent the structure of cognitive processes in the domains of cognitive processing and cognitive development. Hierarchical unidimensional theories consisting of a single sequence of stages through which development proceeds in one direction only have predominated. However, a review of stage theories revealed that a two-dimensional, interactive (multidimensional) structure is warranted. Particularly in the area of cognitive development, results of research have supported subdivision of the stages of prominent unidimensional theories. Following this trend a small number of theorists have developed multidimensional theories, most of which consist of a sequence of stages in which each stage contains a number of subsidiary stages or levels. The emergence of a similar trend in other domains is examined, and the prospects of using an existing multidimensional framework to enable future comparisons and integration of different stage theories is explored.     

Sexuality and cyberporn: Towards a new agenda for research

This article presents theoretical considerations based on cultural analysis approaches to studying pornography and sexuality as a means of starting to suggest a new agenda for cyberporn research. By bringing to the forefront concepts of how subjectivity and sexuality are produced within the computer/Internet apparatus, I hope to diversify the focus in cyberporn research away from social science approaches and pre-Foucaultian assumptions of the subject which obscure understandings of new media and cyberporn use. Through a summary of visual culture studies and reception studies of pornography, I argue that cyberporn must be understood as contingent within the encoding and decoding processes and discourses of sexuality (Foucault) in which it is produced and consumed. My focus here is the home office/terminal as the site of reception/cyberporn use. While there is potential for a great variety of cultural analytic approaches to the study of cyberporn and how new media use influences sexuality, I end with specific suggestions for researching cyberporn reception in the home. The computer’s allure is more than utilitarian or aesthetic; it is erotic. Instead of a refreshing play with surfaces, as with toys or amusements, our affair with information machines announces a symbiotic relationship and ultimately a mental marriage to technology. Rightly perceived, the atmosphere of cyberspace carries the scent that once surrounded Wisdom. The world rendered as pure information not only fascinates our eyes and minds, but also captures our hearts. We feel augmented and empowered. Our hearts beat in the machines. This is Eros. (Michael Heim, The Metaphysics of Virtual Reality)     

Calculating and graphing within-subject confidence intervals for ANOVA

The psychological and statistical literature contains several proposals for calculating and plotting confidence intervals (CIs) for within-subjects (repeated measures) ANOVA designs. A key distinction is between intervals supporting inference about patterns of means (and differences between pairs of means, in particular) and those supporting inferences about individual means. In this report, it is argued that CIs for the former are best accomplished by adapting intervals proposed by Cousineau (Tutorials in Quantitative Methods for Psychology, 1, 42–45, 2005) and Morey (Tutorials in Quantitative Methods for Psychology, 4, 61–64, 2008) so that nonoverlapping CIs for individual means correspond to a confidence for their difference that does not include zero. CIs for the latter can be accomplished by fitting a multilevel model. In situations in which both types of inference are of interest, the use of a two-tiered CI is recommended. Free, open-source, cross-platform software for such interval estimates and plots (and for some common alternatives) is provided in the form of R functions for one-way within-subjects and two-way mixed ANOVA designs. These functions provide an easy-to-use solution to the difficult problem of calculating and displaying within-subjects CIs.     

Optimal sample sizes for precise interval estimation of Welch’s procedure under various allocation and cost considerations

Welch’s (Biometrika 29: 350–362, 1938) procedure has emerged as a robust alternative to the Student’s t test for comparing the means of two normal populations with unknown and possibly unequal variances. To facilitate the advocated statistical practice of confidence intervals and further improve the potential applicability of Welch’s procedure, in the present article, we consider exact approaches to optimize sample size determinations for precise interval estimation of the difference between two means under various allocation and cost considerations. The desired precision of a confidence interval is assessed with respect to the control of expected half-width, and to the assurance probability of interval half-width within a designated value. Furthermore, the design schemes in terms of participant allocation and cost constraints include (a) giving the ratio of group sizes, (b) specifying one sample size, (c) attaining maximum precision performance for a fixed cost, and (d) meeting a specified precision level for the least cost. The proposed methods provide useful alternatives to the conventional sample size procedures. Also, the developed programs expand the degree of generality for the existing statistical software packages and can be accessed at brm.psychonomic-journals.org/content/ supplemental.