2.6. Data analysis
All tests were scored though the use of scoring rubrics and
the resulted student performance scores were analyzed by
using (a) one-way ANOVA for the comparison of the pre-test
scores of the five groups on each test and (b) one-way
ANCOVA for the comparison of the post-test scores of the
five groups on each test. For the latter procedure, the students’
scores in the corresponding pre-tests were used as the cova-
riate. The aim of the first procedure was to determine whether
the five groups of the study were comparable with regard to
the sample’s entry understanding of physics concepts from the
subject domain of
H
&
T
, before the study and before each
section. The aim of the second procedure was to investigate
whether the five groups of the study had differences on the
outcome measures (understanding of physics concepts in the
domain of
H
&
T
) of each test. For all analyses the effect size
(partial
h
2
;
Cohen, 1988
) is reported.
The second way involved the identification and classifica-
tion of students’ scientific and non-scientific conceptions
concerning temperature, changes in temperature, heat, heat
transfer, heat capacity, and specific heat through the use of
qualitative thematic analysis. A sample of the qualitative
analysis concerning conceptions of specific heat is included in
Table 3
.
In addition, the percentage for each one of the resulting
conceptions was calculated. The aim of the latter was to
compare whether the prevalence of students’ conceptions
changed after the treatments of the study. This procedure was
essential because it clarified whether students of similar scores
shared the same ideas or not, either scientifically acceptable or
scientifically not acceptable ones.