Análisis no paramétrico de la interacción de dos factores mediante el contraste de rangos alineados / An aligned rank test for a nonparametric analysis of the two way interaction

Problemas que requieren un análisis no paramétrico de la interacción surgen con cierta frecuencia en estudios del comportamiento. Hay, sin embargo, una ausencia de procedimientos en paquetes estadísticos usuales como SAS o SPSS. El objetivo del presente trabajo es revisar los fundamentos del contraste de rangos alineados en dos diseños de investigación de dos factores de amplio uso en Psicología. El procedimiento ha mostrado buenas propiedades en numerosas distribuciones no normales tanto en control del Error Tipo I como en potencia o sensibilidad estadística. Es fácilmente ejecutable mediante programas estadísticos comunes y se ilustra paso a paso con el módulo del modelo lineal general de Spss. Se aplica a dos estudios de caso donde aparecen diferencias de género en habilidades lingüísticas en niños ciegos no detectadas con otros procedimientos. Limitaciones al contraste de rangos alineados se han observado en situaciones de heterogeneidad de covarianzas entre grupos, y también con tamaños muestrales inferiores a diez participantes por condición. Su uso adecuado tras el diagnóstico de supuestos puede aumentar la sensibilidad de detección de efectos comportamentales de interés teórico o aplicado (AU)

Research problems that require nonparametric analysis of the interaction frequently arise in the behavioral sciences. There is, however, a lack of available procedures in commonly used statistical packages such as SAS or SPSS. The purpose of the present study is to review the fundamentals of the aligned rank test for two widelyused two-way research designs in psychology. The procedure has shown good properties in nonnormal distributions in terms of Type I Error control and statistical power. It is easily conducted using common statistical packages. It is applied to two case studies which result in gender differences in linguistic abilities in blind children not revealed by other procedures. Limitations of the aligned rank test have been observed in situations of covariance heterogeneity across groups, and also with sample sizes smaller than ten participants per condition. Its adequate use after model diagnostics can, however, increase sensitivity to detect behavioral effects of theoretical or practical interest (AU)

Family and ability correlates of academic grades: social status group differences.

In a continuation of work by Marjoribanks (2003), using a sample of 150 seventh grade students, relationships among Parent Involvement as defined by factor scores of four measures of parents' involvement completed by teachers: teacher-parent contacts, teacher-parent communication, parents' involvement at home, and parents' participation in school, Intellectual Ability as defined by Verbal Intelligence using the Yuste's Differential and General Aptitudes Battery-M, and Academic Grades as defined by the average grade for all subject matter were examined. Analysis showed different predictive models for children's academic achievement as a function of social status. For children of low and middle social status, Intellectual Ability was the single predictor. For children of high social status the predictors were Parents' Involvement and the interaction of Parents' Involvement and Intellectual Ability.