One of the most widely used scales for the evaluation of stress is the Perceived Stress Scale (PSS), and it has been adapted into different languages. However, few studies have presented normative data from large samples, and there do not appear to be any studies of the PSS that provide normative data based on large samples for Mexico. Thus, the goal of this study was to provide normative data regarding gender and different age groups for a sample of 1990 Mexican subjects to validate the factor structure of the construct for this sample. The analysis of the 10- and 14-item versions of the PSS revealed that the scale had adequate reliability and that the factor structure was consistent with previous studies. With respect to the normative data, the means of the different groups ranged from 20.93 to 25.63 for the PSS14 and from 14.52 to 17.73 for the PSS10. We propose that scores within one standard deviation of these means be used as reference values for each group.

As a fundamental part of their chemical education, first-year undergraduate students are substantially involved in laboratory activities. Despite the specific teaching staff choices on the main laboratory aims, students normally receive a vast amount of information during these activities. Apart from understanding theoretical content, fundamental skills such as manipulation, data collection and interpretation should be developed. In this context, learners could feel overwhelmed since they can only process a few pieces of information at a time. Indeed, our experience at theUniversidad de la República(Uruguayan public university) shows that many first-year students are in fact not able to cope with all the information they receive during laboratory activities. As a result, many of them only follow the experimental protocol automatically, without gaining significant knowledge or developing the necessary skills. In this work, we assessed the use of new online interactive pre-laboratory activities implemented for 252 first-year university students enrolled in a 12-module General Chemistry laboratory course. The student choice of interactiveversusmore traditional material was evaluated together with observed preferences regarding the different interactive tools offered. Besides, an online pre-laboratory discussion forum was also implemented and assessed. Both the interactive material and the discussion forum were chosen freely by the majority of students (61% and 79%, respectively). Interestingly, the choice was to some extent modulated by student previous performance. Interactive pre-laboratory material was more frequently chosen by low previous performance students, whereas pre-laboratory forum was preferentially used by high previous performance students. Finally, the influence of these new materials on student laboratory performance was statistically analyzed. Other personal and academic variables were also taken into account. Interactive material access was positively correlated with the final laboratory marks for medium previous performance learners. On the other hand, for lower previous performance students, the academic discussion between teachers and partners promoted by the online forum was positively correlated with their academic performance.

The aim of this study is to confirm the factor structure of a self-report measure of achievement goal tendencies (Hayamizu & Weiner, 1991) described in previous research, and examine the reliability and validity of scores in a sample of Uruguayan university students. A theoretical three-factor model is proposed (learning, performance and outcome goals), as well as one-factor models for each goal. Confirmatory factor analyses show that all models are identified, and solutions are conceptually correct. Our results suggest that outcome goals could be split into two correlated sub-dimensions related to achievement time (short and long term goals). Concurrent and predicted validity were established through significant correlations with perceived ability and academic achievement respectively. Conceptualisation of these findings and suggestions for future research are discussed.