## 3 Results
### Questionnaire Analysis  
Table 2 shows the results of UES sub-scales for each of the 12 sample users. Results reported in Table 3 indicate that the platform had an acceptable level of engagement with 62.51%. In the breakdown of the scale, it can be found that the sub-scale with the highest percentage of responses was NO (75.00%), which means that a higher users' level of interest in the platform and curiosity was evoked by the system and its contents. On the other hand, the sub-scale with the lowest percentage value was FA, with 55.24%, suggesting that perhaps the setting of the simulator is slightly dispersive; thus, the participants would possibly recommend the platform with a likelihood of returning to use the EVA learning environment.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sub-Scale** & **No. Items** & **Cronbach’s Alpha** & **Mean** & **Standard Deviation** \\ \hline Aesthetics (AE) & 5 & 0.957 & 4.100 & 0.437 \\ Focused attention (FA) & 5 & 0.600 & 3.767 & 0.786 \\ Felt involvement (FI) & 3 & 0.840 & 4.194 & 0.952 \\ Perceived usability (PU) & 8 & 0.817 & 4.146 & 0.785 \\ Novelty (NO) & 3 & 0.947 & 5.250 & 0.655 \\ Endurability (EN) & 5 & 0.770 & 3.817 & 0.771 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Sub-scales, items, and sub-scale means and standard deviation of user engagement scale (UES).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample User** & **AE** & **FA** & **FI** & **PU** & **NO** & **EN** \\ \hline
1 & 2.80 & 4.60 & 5.67 & 5.50 & 4.33 & 3.20 \\
2 & 6.20 & 4.40 & 3.00 & 6.00 & 7.00 & 5.80 \\
3 & 4.60 & 2.60 & 3.67 & 5.75 & 6.00 & 3.40 \\
4 & 5.00 & 5.60 &  
The UES sub-scales were all positively correlated (Table 4); the correlation of the aesthetics sub-scale with focused attention, felt involvement, perceived usability, and novelty sub-scales was moderate. According to the correlation guide suggested by [PERSON] (1986), in which correlation values ranging from 0.00 to 0.19 indicate a \"very weak\" correlation, values ranging from 0.20 to 0.39 indicate a \"weak\" correlation, values between 0.40 and 0.59 are considered as \"moderate\" correlations, values between 0.60 and 0.79 are considered \"strong\" correlations, and values that range from 0.80 to 1.0 are considered as \"very strong\" correlations, there is a very weak correlation between FI and PU (0.16) and between FI and EN (0.32) sub-scale elements, and there is a weak correlation between AE and FI (0.26), AE and NO (0.37), FA and PU (0.27), FA and NO (0.24), and PU and NO (0.24) sub-scale elements. Moderate correlation results can be found between AE and FA (0.57), FI and NO (0.49), and NO and EN (0.56) elements, while a strong correlation exists between AE and PU (0.79), FA and FI (0.69), FA and EN (0.63), and PU and EN (0.70) elements. Lastly, a very strong correlation exists between AE and EN (0.92).  
From these results, in particular focusing on strong correlations, it is visible how the aesthetics sub-scale is correlated with the other sub-scale elements; thus, the feedback on the visual appeal may be considered the first aspect to take into account when developing virtual products or services, particularly in the learning domain. The correlation between focused attention and felt involvement and between focused attention and endurability shows that the phase of design of a virtual service must consider the necessity for the user to be engaged in the tasks not only because of the final aim, e.g., the learning process for becoming an entrepreneur, but also because of the elements accompanying the environment and making the user, in this case the learner, appreciate the product (visual appeal, intuitiveness, usability, sense of curiosity).  
To compare the level of engagement emerging from the questionnaires and the level of activation defined through the SVM expression classification, median values of the scores assigned by each participant to the UES items on the seven-point Likert scale were calculated.