MDMA Cmax vs Dosis Oral
1.3 Estudios de actividad metabólica
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The current section examines the relationships between the personal characteristics variables and academic performance. It begins by examining the relationship gender had with academic performance and moves on to consider the prior performance variables and SES.
SES and grades
As discussed in Section 3.3.1, it was expected that SES and grades would be posi- tively associated. Results from large-scale meta-analysis discussed in Section 3.3.1 indicated the correlational relationship between SES and grades was positive and approximated to 0.22. However, sensitivity analysis across all sets in study 1 in- dicated that SES (Scaled) was negatively correlated with all the study’s academic performance indicators (coursework, final exam, and semester grades). In study 1, (see Table 5.4), the correlation between SES (Scaled) and semester grades was statistically significant, where r = -0.25, p < 0.01. Indeed, the correlations were statistically significant in six out of eight sets, with a mean correlation value of - 0.253 indicated (see Appendix, Table B.3). A similar pattern emerged in study 2. At Time 1 and 2 and across all sets, SES (Scaled) was negatively (but not always statistically significantly) correlated with all the study’s criterion variables (see Ap- pendix, Tables B.18 and B.28), with mean correlation values ranging from -0.128 (for final exams) to -0.176 (for mid-term exam) indicated.
In regression analysis in study 1, SES (Scaled) emerged as a statistically signif- icant negative predictor of coursework and semester grades in models 1 and 3. For instance, in study 1, SES (Scaled) was a negative predictor of semester grades in model 1 after controlling for prior performance and motivational resources, where
β = -0.304, p = 0.002 (See Appendix, Table B.56). SES (Scaled) was also a nega-
tive (albeit non-statistically significant) predictor of final exam scores in study 1 in models 1 and 3.
6.1. Answering the research questions (RQs) 127 semester grades. For example, in study 2 at Time 2, SES (Scaled) was a negative predictor of semester grades in model 1, after controlling for prior performance and motivational resources, where β = -0.434, p = 0.009. SES (Scaled) (see Appendix, Table B.70).
In summary, the correlation and regression results in study 1 and 2 concurred, indicating that SES and academic achievement were negatively associated in the current study, often statistically significantly so, with betas not less than -0.3 in all the model 1 analyses except one (Study 1, Final exams). This negative association was contrary to expectations, where higher SES was expected to be accompanied by more social and capital resources, which in turn was expected to facilitate better academic outcomes (Bourdieu, 1986). These findings are returned to in Section 6.2. Prior performance and grades
As discussed in Sections 3.3.2 and 3.3.3, it was expected that the relationship be- tween prior performance and grades would be positive and small to medium-sized. In study 1, the correlations IELTS exam, GPA (English), and GPA (All subjects) had with semester grades were small but statistically significant, where r = 0.22,
p < 0.01, r = 0.27, p < 0.01, and r = 0.29, p < 0.01 respectively (see Table 5.4).
Sensitivity analyses indicated that the mean correlation value for GPA (English) and semester grades was 0.21 (see Table B.6). It should be noted, however, that the correlation was only statistically significant in one set. IELTS score and final exam score, and IELTS score and semester grades were, by contrast, statistically significantly correlated in seven out of eight and six out of eight sets respectively.
Regression analyses in study 1 revealed that in regression model 3, IELTS score was a statistically significant predictor of final exam scores, where β = 0.356, p < 0.001 (see Table 5.6). GPA (English) was also retained in model 3 as a statistically significant predictor of semester grades, where β = 0.23, p ≤ 0.01 (see Table 5.7).
In study 2, GPA (All subjects) and IELTS were removed from the analysis because of the large number of missing cases (51 for the former and 38 for the latter), which left GPA (English) as the sole prior performance indicator. Sensitivity analysis indicated that the relationship between GPA (English) and mid-term results
6.1. Answering the research questions (RQs) 128 was generally marginal (i.e., below a value of 0.1 in most or all sets) (see Appendix, Table B.16). The relationship between GPA (English) and the study’s criterion variables was mostly small at Time 2 (see Appendix, Table B.26). For instance, sensitivity analysis indicated the correlational relationship between GPA (English) and semester grades across sets generated a mean correlation value of 0.104.
In study 2, regression analysis indicated that in models 1, 2, and 3a, at Times 1 and 2, and across all the criterion variables, GPA (English) was not a statistically significant predictor, which was contrary to expectations. Examining the variable further, in study 2 the mean score for this variable was 86% (N = 73), which was similar to that in study 1, 90% (N = 166). In other words, the average grade that students received in study 2 was only 4 per cent less than that in study 1; yet the students in study 2 had, after twelve years of English, only achieved an IELTS band that categorised them as low-intermediate learners, failing to achieve an overall Band 5 (unlike the participants, their peers, in study 1) and proving themselves to be in need of additional semesters in remedial English. This seems to suggest that some of the grades awarded by some of the schools responsible for the GPA (English) scores in study 2 were unreflective of the students’ actual English abilities. Thus, in contrast to the students in study 2, those students in study 1 who achieved high scores in their GPA (English) may generally have deserved their scores - if their far better performance on the IELTS exam can be taken as a guide.
In summary, the prior performance indicator GPA (English) was more reflective of actual abilities for more students in study 1 than in study 2 if the variable’s success at predicting semester grades in the relevant course can be taken as a guide. The differing relationship that GPA (English) had with the criterion variables in study 1 and 2 is discussed further in Section 6.2. Interestingly, when an additional model (Model 3b) was run in study 2 and mid-term results were included, GPA (English) appeared consistently as a statistically significant predictor of coursework, where β = 0.353, p < 0.001. Thus, although there are doubts (as expressed above) about the quality of the GPA (English) variable in study 2, it cannot be dismissed as an entirely inaccurate reflection of EFL ability (or willingness to work) for all the students in the study with regression analysis results indicating that at least some of
6.1. Answering the research questions (RQs) 129 the students may have deserved their higher GPA (English) grade. Unfortunately, it cannot be known which students received more accurate (i.e., deserved) GPA (English) grades and which did not. Nor can it be known which bodies (public and private schools) or specific institutions tended to award more or less accurate GPA (English) grades.
Gender and grades
As discussed in Section 3.3.4, it was expected that males would perform worse than females. As a reminder, males were coded as ‘1’ and females as ‘0’. In study 1 (see Table 5.4), gender was statistically significantly negatively correlated with coursework score (r = -0.39, p < 0.01), which was consistent with this expectation. Splitting the file indicated that the mean coursework score for females in study 1 was 81.3 per cent (SD = 9.36), and for males, it was 71 per cent (SD = 13.78). The difference between the male mean coursework score and the female mean coursework score was associated with a large effect size, where Hedges’ g = 0.97, 95% CI [0.60, 1.33]; that is, one that was found to approximate to Cohen’s (1988) convention for a large effect. Sensitivity analysis indicated gender was statistically significantly negatively correlated with coursework scores across all eight sets, with a mean cor- relation value of -0.41 indicated (see Appendix, Table B.2). Why females achieved better coursework scores in study 1 is uncertain, but it appears females were more willing to complete coursework tasks. As might be expected (because semester grade was not independent of coursework), gender and semester grade were also negatively correlated. In contrast, the correlation between final exam and gender was marginal (see Appendix Table B.2).
Regression analysis results in study 1 revealed gender to be a statistically sig- nificant predictor of coursework grades both in model 1, where β = -0.484, p < 0.001 (see Table B.56), and in model 3, where β = -0.506, p < 0.001 (see Table 5.5). Gender was also a statistically significant predictor in model 1 of semester grades in study 1, where β = -0.291, p = 0.004 (see Appendix, Table B.60).
In contrast to the results in study 1, in study 2 gender was only marginally and non-statistically significantly correlated with all of the criterion variables across all
6.1. Answering the research questions (RQs) 130 sets. Similarly, gender was not a statistically significant predictor for any criterion variable in any regression model in study 2.
In summary, these results suggest that the male participants in study 1 were less willing to complete the many small tasks that composed the coursework grade compared to those in study 2. This may have been related to the structure of the courses, an idea that is explored more fully in Section 6.2.
RQ2: The overall pattern of results
Overall, results indicated that the relationship between SES and academic achieve- ment was negative. This was evident across studies, sets of assumptions, and forms of analysis (i.e., both correlational and regression). In contrast, the relationship GPA (English) had with grades varied across studies. In study 1, the relationship was small, albeit occasionally statistically significant in correlation and regression analyses. In study 2, although the relationship became less marginal at Time 2 than Time 1, only in a few cases was there a statistically significant correlation. In no regression models in study 2 at Time 1 or 2 was GPA (English) a statistically significant predictor. Generally, therefore, prior performance indicators were better predictors in study 1 than study 2. Finally, where results from the two studies did differ greatly was in regard to gender. In contrast to study 1, gender was not statis- tically significantly correlated with any of the criterion variables in study 2; nor did it appear as a statistically significant predictor in any of study 2’s regression models (see Appendix, Tables B.13 and B.23). The relationship between gender and the study’s criterion variables is discussed more fully in Section 6.2.