## 4 Results
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**VRLE-2**} & \multirow{2}{*}{\
\begin{tabular}{c} **Academic** \\ **Year** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Number of** \\ **Students** \\ \end{tabular} } & \multicolumn{2}{c}{**Question 1**} & \multicolumn{2}{c}{**Question 2**} & \multicolumn{2}{c}{**Question 3**} & \multicolumn{2}{c}{**Question 4**} \\ \cline{3-10}  & & & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) & **Mean** & \(\sigma\) \\ \hline
**TPD** & \multirow{2}{*}{2017–2018} & \multirow{2}{*}{21} & 9.2 & 0.75 & 8.3 & 0.60 & 7.4 & 0.80 & 9.7 & 0.46 \\
**CL** & & & **-** & **-** & **-** & **-** & **-** & **-** & **-** & **-** & **-** \\ \hline
**TPD** & \multirow{2}{*}{2018–2019} & \multirow{2}{*}{21} & 9.1 & 0.74 & 8.3 & 0.64 & 7.3 & 0.73 & 9.8 & 0.44 \\
**CL** & & & 9.5 & 0.46 & 9.8 & 0.33 & 9.2 & 0.58 & 9.8 & 0.54 \\ \hline
**TPD** & \multirow{2}{*}{2019–2020} & \multirow{2}{*}{11} & 8.8 & 0.75 & 8.2 & 0.60 & 7.6 & 0.66 & 9.6 & 0.50 \\
**CL** & & & 9.6 & 0.38 & 9.8 & 0.34 & 9.3 & 0.34 & 9.7 & 0.47 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mean and standard deviation (\(\sigma\)) of students’ scores from surveys given from 2017 to 2020 to each question of the Table 1 for VRLEs developed later (VRLE-2, Figure 4). Figure 6: KPIs values of the VRLE of TPD over a period of academic years (former version, VRLE-1, and later version, VRLE-2). As can be seen in Figures 6 and 7, there are two similar evolutions: (i) the values of both motivation (question 1) and interactivity (question 2) decrease over time until the VRLE is updated (VRLE-2); (ii) the values of both ease of use (question 3) and utility (question 4) remain constant throughout the period of time evaluated. Looking at the VRLE-1 case, the KPI corresponding to motivation (question 1) has an average value of 8.6 (TPD) or 7.5 (CL) in the first academic year evaluated, decreasing this value year after year until reaching a value of 7.5 (TPD) and 6.9 (CL) in the last year of use. The interactivity KPI (question 2) is similar to the aforementioned, that is, at the beginning of the VRLE-1 usage, the interactivity KPI has an average value of 7.5 (TPD) and 9.0 (CL), which drops in each course until reaching a value of 6.2 (TPD) and 7.5 (CL) in the last course evaluated. By contrast, as seen in Table 2, this decreasing trend changes in both KPIs just at the moment when the period of use of VRLEs-2 begins. In particular, the motivation KPI reaches a value of 9.2 (TPD) and 9.5 (CL) at the beginning of the period of use of these new versions of VRLEs. Similarly, one can observe in the interactivity KPI of the VRLE that the values reach 8.3 (TPD) and 8.3 (CL) at the beginning of the use of the updated version (VRLE-2). Regarding standard deviation values, results shown in Table 2 indicate a low dispersion of the students' feedback (the maximum value is 1.03). From Tables 2 and 3, as well as Figures 6 and 7, it is verified that the KPIs corresponding to the ease of use (question 3) and usefulness (question 4) have values that vary little throughout the period of time studied, regardless of the version of VRLE used. Thus, the ease of use KPI acquires values between 7.6-7.0 (TPD) and 9.3-8.9 (CL). In addition, the usefulness KPI acquires values ranging between 9.8-9.7 (TPD) and 9.8-9.6 (CL). In both of these KPIs the standard deviation is low, never exceeding 0.83, which indicates that there is little dispersion in the individual assessments taken from the surveys and, consequently, the opinion of the student body is quite homogeneous. time, thus using feedback from the users to avoid the loss of quality of a program also acquires a great relevance [11].