Maria Knobelsdorf, University of Dortmund, Germany - Didaktik der ...

formatics. The final sample of respondents was comprised of 115
Students. From the total of students, 55 (47.8%) attended the 3 rd
of Greek Lyceum (16-17 years), 29 (25.2%) the 11 th or 12 th of a
German Gymnasium (16-18 years) and 31 (27.0%) the first year
of study at the Department of Informatics (17-18 years). 88 of the
students were males (76.5%) and 27 (23.5%) females.
4.2 Data Analysis and Results
As proposed by Fornell and Larcker [9], there are three procedures
to assess the convergent validity of any measure in a study:
1) Composite reliability of each construct, 2) Item reliability of
the measure and 3) The average variance extracted (AVE).
Therefore, we started with an analysis of composite reliability and
dimensionality to check the validity of the scale used in the questionnaire.
Concerning the reliability of the scales, Cronbach (CR)
α indicator was applied [7] and inter-item correlations statistics
for the items of the variable were calculated. As stated by to Fornell
& Larcker [9], CR α value greater than 0.7 indicates a high
reliability. Table 1 demonstrates the result of the test that revealed
acceptable indices of internal consistency in all the factors.
Table 1. Summary of Measurement Scales
Factors Items Mean S.D. CR Loads AVE
PE PE1 4.52 1.95 0.93 0.74 0.67
PE2 4.16 1.75 0.85
PE3 4.40 1.72 0.84
PE4 4.51 1.69 0.83
STF STF1 4.97 1.51 0.92 0.72 0.62
STF2 4.98 1.58 0.73
STF3 5.47 1.61 0.86
STF4 5.23 1.68 0.82
SI SN1 4.04 2.00 0.82 0.76 0.63
SN2 4.12 2.04 0.82
SEF SEF1 3.89 1.79 0.71 0.82 0.56
SEF2 4.19 1.73 0.70
SEF3 2.62 1.69 0.72
BI BI1 4.90 2.09 0.96 0.82 0.73
BI2 4.87 2.03 0.87
BI3 4.36 2.07 0.88
CPS CPS1 4.88 1.46 0.88 0.76 0.54
CPS2 4.89 1.44 0.75
CPS3 4.79 1.57 0.83
CPS4 4.36 1.62 0.58
C(CL)C CCC1 5.31 1.69 0.91 0.61 0.53
CCC2 5.13 1.60 0.85
CCC3 4.84 1.76 0.62
CLC1 5.50 1.59 0.71
CLC2 5.11 1.58 0.77
CLC3 5.03 1.55 0.78
CDS CDS1 4.74 1.68 0.90 0.80 0.59
CDS2 4.44 2.03 0.83
CDS3 4.82 1.84 0.82
CDS4 4.48 1.97 0.75
CDS5 4.07 1.92 0.63
The reliability of an item was assessed by measuring its factor
loading onto the underlying construct. Hair et al. [12] recommended
a factor loading of 0.5 to be good indicator of validity at
the item level. The factor analysis identified eight distinct factors
(Table 1): 1) Performance Expectancy (PE), 2) Satisfaction (STF),
3) Social Influence (SI), 4) Self-Efficacy (SEF), 5) Behavioral
Intention (BI), 6) Confidence with Problem Solving (CPS), 7)
Confidence for using Data Commands (Conditional-Loop)
(C(CL)C) and 8) Confidence for Data Structures (CDS).
The third step for assessing the convergent validity is the average
variance extracted (AVE); AVE measures the overall amount of
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variance that is attributed to the construct in relation to the amount
of variance attributable to measurement error. Convergent validity
is found to be adequate when the average variance extracted is
equal or exceeds 0.50 [16].
To examine the research questions regarding the differences in
students’ perceptions among German Gymnasium, and CS freshmen,
we used an Analysis of Variances (ANOVA), including the
eight factors as dependent variables and the students’ group as
independent variable. As we can see from the outcome data in
Table 2, students’ group has a significant impact on students’ PE,
STF, SI, BI and CDS. On the other hand students’ group does not
exhibit significant difference on students’ SEF, CPS and C(CL)C.
Table 2 displays our results regarding the significance of the
differences, while Figure 3 shows the average results for each
factor over the groups. SEF, CPS and C(CL)C have no significance
difference among the three groups and from Figure 2 we
can notice that these factors are on the same levels at each group.
On the other hand PE, STF, SI, BI and CDS do have significant
differences among the groups and in some cases these difference
are quite remarkable (i.e., BI, PE).
Table 2. The differences among the students’ groups
Factor Mean (S.D.) F Result
Lyceum Gymnas. CS
(GR) (GE) Freshmen
PE 4.10 (1.58) 3.75 (1.70) 5.61 (0.79) 14.97** S.D.
STF
SI
5.03 (1.39)
3.54 (1.90)
4.65 (1.67)
3.93 (1.79)
5.90 (0.90)
5.19 (1.34)
6.86**
9.15**
S.D.
S.D.
SEF 3.58 (1.35) 3.77 (1.61) 3.34 (0.94) 0.78 I.D.
BI 3.94 (1.97) 4.48 (1.59) 6.24 (0.90) 17.11** S.D.
CPS 4.51 (1.46) 4.84 (1.44) 5.06 (0.79) 1.81 I.D.
C(CL)C 5.14 (1.37) 4.74 (1.52) 5.55 (1.10) 2.73 I.D.
CDS 4.10 (1.44) 4.66 (1.82) 5.08 (1.51) 4.03* S.D.
**p