2.4. Data Analysis

For the basic descriptive analysis the statistical software program IBM SPSS^® (IBM Corp, Armonk, NY, USA) version 22.0 for Windows was used. The program IBM AMOS^® 23 (IBM Corp, Armonk, NY, USA) was employed with the purpose of analyzing the existing relationships between the constructs included in the structural model. Following development of the theoretical model a path analysis was conducted which considered the correlation matrix developed via a multi-group analysis, grouping participants according to sex. Finally, two different structural models were configured with the purpose of confirming whether the associations between the studied variables varied as a function of the sex of adolescents.

The path models were formed by nine observable variables and two latent variables in order to determine the indicators (Figure 1). Causal explications of the latent variables are given by the proposed models via the relationships observed between the indicators, whilst also considering the reliability of measurements. Similarly, measurement error is included for the observable, variables enabling it to be directly controlled. The unidirectional arrows represent lines of influence between the latent and observable variables, with these being interpreted as multivariate regression coefficients. Bidirectional arrows show the relationship between the latent variables and are also represented by regression coefficients.

Theoretical Model. Note: TC, task climate; CL, cooperative learning; E/I, effort/improvement; IR, important role; EC, ego climate; MR, member rivalry; PM, punishment of mistakes; UR, unequal recognition; PA, physical activity; AP, academic performance; and STRESS, life stress.

Task climate (TC) and ego climate (EC) act as exogenous variables with each one being inferred by three indicators. The indicators relating to task climate are IR (important role), E/I (effort/improvement), and CL (cooperative learning). With regards to ego climate, the indicators are PM (punishment of mistakes), UR (unequal recognition), and MR (membership rivalry). Level of participation in physical activity (PA) acts as an endogenous variable which receives the effects of the task climate (TC) and the ego climate (EC). Academic performance (AP) acts as an endogenous variable, receiving the effects of the task climate (TC), the ego climate (EC), participation in physical activity (PA), and life stress (STRESS). Likewise, life stress (STRESS) acts as an endogenous variable, receiving the effects of the task climate (TC), the ego climate (EC) and participation in physical activity (PA).

Model fit was checked with the purpose of verifying compatibility of the model with the observed empirical information. Reliability of model fit was established according to the goodness of fit criteria proposed by Marsh [37].