Regression with compositional response or covariates, or even regression between parts of a composition, is frequently employed in social sciences. Among other possible applications, it may help to reveal interesting features in time allocation analysis. As individual activities represent relative contributions to the total amount of time, statistical processing of raw data (frequently represented directly as proportions or percentages) using standard methods may lead to biased results. Specific geometrical features of time budget variables are captured by the logratio methodology of compositional data, whose aim is to build (preferably orthonormal) coordinates to be applied with popular statistical methods. The aim of this paper is to present recent tools of regression analysis within the logratio methodology and apply them to reveal potential relationships among psychometric indicators in a real-world data set. In particular, orthogonal logratio coordinates have been introduced to enhance the interpretability of coefficients in regression models.

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Our study estimates the prevalence of Internet addiction in Czech adolescents as well as differences by gender and school type. A total of 3,950 adolescents (n = 1,940 boys, n = 2,010 girls) from 11 to 19 years of age (M = 15.73, SD = 1.99) participated in the research. They completed the Internet Addiction Test, which consists of subscales for Salience, Excessive Use, Neglect Work, Anticipation, Lack of Control, and Neglect Social Life. The results indicate that adolescent girls have higher levels of internet addiction. In boys, unlike girls, internet addiction was associated with a reduction in social relationships and interactions. Our findings show interesting differences between adolescent girls and boys and the type of school attended in the Czech population in terms of Internet addiction.

This intensive exploratory research maps the working conditions of school psychologists in the Czech Republic. An electronic questionnaire consisting of 71 questions (58 quantitative, 13 qualitative) from nine fields was used as a research tool. The respondent sample (N = 63; 53 females, 10 males) indicate that they are largely job-satisfied and there is significant statistical relationship between their job satisfaction and their acceptance by both management and teaching staff. Compared to prior years, these school psychologists appear more certain of their work identity.