Research in Engineering Education Symposium 2011 - rees2009

Universidad Politécnica de Madrid (UPM) Página 471 de 957
Academic results. Experimental versus control group
This section presents the results of midterm theme 3 evaluation. As indicators of student
performance, we have comparing mean groups for scores for three classes: EG, CG1 and
CG2 in Table 5.
The test hypothesis is that the values obtained from two different groups are equal. If the
groups are independent of each other and the data are normally distributed in each group,
then a group t test can be used as it was done in this work using the SAS/ETS PROC TTEST
from SAS Institute Inc, SAS V9.2. The "Equality of Variances" test results show that the
assumption of equal variances is reasonable for these data (the Folded F statistic F' = 1.32,
with p=0.2500). The assumption of normality has been checked using PROC UNIVARIATE;
so the appropriate test is the usual pooled test, which shows that the average scores of
partial exam of Theme 3 for CG1 and EG as well CG2 and EG are significantly different at
the 5% level (t=-4.52, p=0.0001 for the former and t=-3.05, p=0.0027 for the latter), So the
experience can be considered positive because it has contributed to improve academia
results in the midterm exam.
Table 5: Mean marks. Midterm Theme 3 exam. Experimental Group versus Control groups
Additionally in Fig 1, it is shown the percentage of students (%) belonging to EG and CG1-
CG2 groups achieving marks of