Second-Year College Students’ Scientific Attitudes and Creative Thinking Ability: Influence of a Problem-Based Learning (PBL) Chemistry Laboratory Course - Affective Dimensions in Chemistry Education - page 220

5.2 Students ' Creative Thinking Abilities

Comparisons were first made between the posttest scores of the two groups of
students

creative thinking abilities in the three dimensions of the TTCT (fluency,
flexibility, and originality) as well as on the overall TTCT scores using the Mann-
Whitney U test analysis procedure. This analysis was performed in response to the
second research question (How does the PBL chemistry laboratory course influence
students

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creative thinking abilities in the dimensions of fluency, flexibility, and
originality compared to students in the comparison group who were instructed in
the traditional course?). The results of the analysis indicate that the differences
between the mean scores of the three dimensions of the TTCT as well as for the
overall instrument were statistically significant in favor of the treatment group (see
Table 5 ). At the same time, the approximate effect size (as categorized by Cohen,
1988 ) of the difference between the treatment group and the comparison was
relatively small for all the three dimensions as well as for the whole instrument.
The Wilcoxon signed-rank tests were next conducted to compare the differences
between the pretest and posttest rank mean scores for each of the three dimensions
for the treatment and comparison groups as well as for the overall attitudes
instrument (see Tables 6 and 7 ).

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Table 5 Comparisons of the posttest mean TTCT scores in the three dimensions between the
treatment group ( N ¼ 20) and the comparison group ( N ¼ 26) using the Mann-Whitney U test

Mean rank

Treatment
group

Comparison
group

Mann-
Whitney UZ Sig.

Effect
size Dimensions

Fluency 28.05 20.00 169.00 2.02 0.04* 0.33

Flexibility 30.73 17.94 115.50 3.21 0.00** 0.22

Originality 31.75 17.15 95.50 3.66 0.00** 0.18

Overall
TTCT

30.75 17.92 115.00 3.21 0.00** 0.22

* p 0.01

Note : Effect size is calculated based on nonparametric statistics for the two-group independent
samples design (Grissom & Kim, 2012 )

0.05, ** p

< <

Table 6 Posttest-pretest
mean rank comparisons of the
treatment group on the three
dimensions of the TTCT
using the Wilcoxon signed-
ranks test ( N ¼ 20)

Z

Dimensions Sig. Effect size

Fluency

3.87

0.00** 0.93

Flexibility 3.73 0.00** 0.90

Originality 3.52 0.00** 0.90

Overall TTCT 3.85 0.00** 0.93

** p 0.01

Note : Effect size in terms of the PS (probabilistic superiority)
value is calculated for the two related samples design (Grissom &
Kim, 2012 )

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