## 3 Results and Discussion  
Table 1 summarizes the basic descriptive statistics of the marks obtained by the students who followed the traditional learning methodology (control group) and those who learned using Classcraft(r) (ganification group). It is important to note that the mean mark obtained by the gamification group was higher than that obtained by the control group, suggesting that the use of gamification enhanced the learning ability of the students. In addition, according to the Shapiro-Wilk test, the distribution of the marks of the gamification group followed a normal model but those obtained by the control group did not. These results were validated the Shapiro-Wilk \(p\)-values and the level of significance of \(\alpha=0.05\). Moreover, considering the values of the standard deviation and the coefficient of variation, it seems that the data were more heterogeneous in the gamification group than in the control group. Considering these results, students who used Classcraft(r) showed generally better learning capabilities than those who followed a traditional methodology. After this descriptive study, the Wilcoxon signed-rank test was applied to analyze the median difference of both samples. Considering that the sample size was 38, which was large enough for us to use normal approximation (Z-statistic), the results of this test are shown in Table 2. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Statistic** & **Control Group** & **Gamification Group** \\ \hline Number of cases & 38 & 38 \\ Minimum & 0.6 & 1.5 \\ Maximum & 9 & 10 \\ Arithmetic Mean & 4.69 & 5.63 \\ Standard Deviation & 2.60 & 2.06 \\ Coefficient of Variation & 0.56 & 0.37 \\ Shapiro-Wilk Statistic & 0.92 & 0.96 \\ Shapiro-Wilk \(p\)-value & 0.0098 & 0.2687 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptive statistics about the mark obtained by the students using a traditional methodology (control group) and using Classcraft® (ganification group). \begin{table}
\begin{tabular}{c c} \hline \hline Sum of positive ranks (W\({}^{+}\)) & 133 \\ Sum of negative ranks (W\({}^{-}\)) & 608 \\ Test statistic & 103 \\ Z-statistic & \(-\)3.4444 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of the Wilcoxon signed-rank test. Since the significance level was \(\alpha=0.05\), the critical value was 1.96, and the null hypothesis assuming that the medians of the two samples would be the same was rejected. The average marks regarding the Four C's obtained by students of the gamification and control groups are shown in Figure 1. All marks were higher than 2.5 for all students except for those regarding communication for the students of the control group; the maximum score was five. There was a substantial improvement in the results of the gamification group in comparison with those of the control group, proving that the use of gamification in a classroom can enhance behavior related to the Four C's. The predominant improvement following the use of Classcraft(r) was in creativity (from 2.45 to 3.42), followed by communication (from 2.96 to 3.90). It should be also highlighted that critical thinking seemed to be the best skill in both groups. The significance of the results was analyzed by using the Friedman test and the Nemenyi statistical test. The Friedman test assesses whether the differences in a group of results are significant, while the Nemenyi test evaluates which comparable pairs have significant differences. A significant level of \(\alpha=0.05\) was used. The results of the Friedman test proved that there were statistical differences among the obtained Four C-related marks. The results of the Nemenyi test showed that the students' Four C-related skills were improved thanks to the activities and group project. The Nemenyi test also revealed that critical thinking was better promoted than other skills. A satisfaction questionnaire was filled in by the students at the end of the course. Table 3 shows the average marks for every question in the survey.