Comparing the squared multiple correlation coefficients of non‐nested models: An examination of confidence intervals and hypothesis testing

The performance of the asymptotic method for comparing the squared multiple correlations of non‐nested models was investigated. Specifically, the increase in a given regression model's R² when one predictor is added was compared to the increase in the same model's R² when another predictor is added. This comparison can be used to determine predictor importance and is the basis for procedures such as Dominance Analysis. Results indicate that the asymptotic procedure provides the expected coverage rates for sample sizes of 200 or more, but in many cases much higher sample sizes are required to achieve adequate power. Guidelines and computations are provided for the determination of adequate sample sizes for hypothesis testing.     

Congruence between personality type and environment type as a predictor of stay in an environment

Following Holland's (Making Vocational Choices: A Theory of Careers. Englewood Cliffs, N.J.: Prentice-Hall, 1973) congruence hypothesis, the independent variable in this study is the level of congruence between the personality type of the subjects and the modal personality type in their environment. This variable is hypothesized to predict the two criteria of the study—the inclination to stay and the social acceptance of 71 couples from three settlements. Results show that (a) in each settlement the modal personality type of males is not similar to the modal personality type of females; (b) the correlation between congruence level and inclination to stay in the settlement is .44 (n = 142, p < .01); and (c) the correlations between congruence level and social acceptance are low and not significant. Theoretical and practical implications of the findings are discussed.     

A comparative study of Sr-doped LaMnO3 synthesised via solid-state reaction and sol–gel methods

ABSTRACT

This work deals with the synthesis of hole-doped La_1-xSr_xMnO₃ (x?=?0.25 and 0.33) perovskite via two different ways, namely a solid-state reaction method and a sol–gel process. Various properties of the samples have been investigated and compared by means of different techniques, namely X-ray diffraction (XRD), temperature-dependent resistivity measurements in the temperature range 25–300?K using a closed cycle refrigerator and vibrating sample magnetometry (VSM). All samples have orthorhombic crystal symmetry and an irregular variation in unit-cell volume with increase in Sr content. The average crystallite size was determined from the XRD data and found to lie in the range 19–22?nm. Metal–insulator transitions (MIT) were observed in all the samples via low-temperature electrical characterisations. The magnetic measurements confirm that the magnetisation does not saturate for the 25% Sr doped samples up to the available field of 10?kOe. The magnetic response also supports the interpretation of XRD and resistivity data. The obtained results are explained on the basis of double-exchange and super-exchange mechanisms.     

The dominance analysis approach for comparing predictors in multiple regression

A general method is presented for comparing the relative importance of predictors in multiple regression. Dominance analysis (D. V. Budescu, 1993), a procedure that is based on an examination of the R2 values for all possible subset models, is refined and extended by introducing several quantitative measures of dominance that differ in the strictness of the dominance definition. These are shown to be intuitive, meaningful, and informative measures that can address a variety of research questions pertaining to predictor importance. The bootstrap is used to assess the stability of dominance results across repeated sampling, and it is shown that these methods provide the researcher with more insights into the pattern of importance in a set of predictors than were previously available.     

Differentiation of Self Mediates College Stress and Adjustment

Differentiation of self involves the capacity to modulate affect, maintain a clear sense of self, and balance intimacy and autonomy in significant relationships. Given the central role of family relationships for individual functioning, the authors tested whether differentiation mediated or moderated relations between college stress and personal adjustment. Differentiation of self partially mediated effects of academic and financial stress and exerted a direct influence on adjustment. Limitations, directions for future research, and implications for counseling are discussed.     

Differential Effectiveness of Behavioral Parent-Training and Cognitive-Behavioral Therapy for Antisocial Youth: A Meta-Analysis

Extended the findings from previous meta-analytic work by comparing the effectiveness of behavioral parent-training (BPT) and cognitive-behavioral therapy (CBT) for youth with antisocial behavior problems. Youth demographic variables were also examined as potential moderators of the effectiveness of these 2 types of interventions. Thirty BPT studies and 41 CBT studies met inclusion criteria for this meta-analysis. The weighted mean effect size (ES) for all interventions was 0.40. Youth age was found to moderate the outcome of the 2 interventions, with BPT having a stronger effect for preschool and school-aged youth and CBT having a stronger effect for adolescents. The results also indicate that there may be systematic differences in the outcomes associated with BPT and CBT when the setting of the intervention is considered, suggesting the need to carefully consider the effect of setting in future research. This study also highlights the need for outcome research dealing with more diverse populations and the better classification of research participants on different developmental trajectories of antisocial behavior.