# Analysis of Student Academic Performance Using Human-in-the-Loop Cyber-Physical Systems
## 4 Results and Discussion
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Data Source** & **Attribute** & **Description** \\ \hline \multirow{6}{*}{**Sensing**} & \(\Delta_{Ip}\) & Average time interval (difference between number of hours according to class schedule and the time spent in the university). It is measured with ISABELA application. \\ \cline{2-3}  & _ATU_ & Average time the student stays at the university (h). \\ \cline{2-3}  & \%_Still_ & Average percentage that the student stays without physical activity (still-state). \\ \cline{2-3}  & \%_S_ & Average percentage of sociability calculated with SMSs and calls statistics. \\ \cline{2-3}  & _ND_ & Average number of Bluetooth devices near the student. \\ \cline{2-3}  & \%_Alone_ & Average percentage of time that a student does not have Bluetooth devices nearby. \\ \hline \multirow{6}{*}{**Questionnaire**} & \%_AAQ_ & Average percentage of physical activity reported in the questionnaire. \\ \cline{2-3}  & \%_SSQ_ & Average percentage of sociability state obtained from the questionnaire. \\ \cline{2-3}  & SQ & Average of the Sleep Quality reported by the student in the questionnaire. \\ \cline{2-3}  & _NSH_ & Average number of sleep hours obtained from the questionnaire. \\ \cline{2-3}  & _StudyQ_ & Average of the dedication to study reported by the student in the questionnaire. \\ \hline \multirow{6}{*}{**Academic Database**} & _GPx1B_ & Grade obtained in the first bimester in the subject where this study was applied (value out of 10 points). \\ \cline{2-3}  & _GPx_ & Final grade obtained in the subject where this study was applied (value out of 40 points). \\ \cline{2-3}  & _GPx1B_ & Grade Point Average in the first bimester (value out of 10 points). \\ \cline{2-3}  & _GPx_ & Final grade point average (value out of 40 points). \\ \cline{2-3}  & _CGPA_ & Cumulative grade point average, the academic record of the student in his academic life (value out of 40 points). \\ \cline{2-3}  & _API_ & Academic performance index based on the cumulative GPA and the number of subjects failed (value out of 40 points). \\ \cline{2-3}  & _NC_ & Credit numbers registered by student in this school year. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Description of attributes analyzed. The _CGPA_ and _API_ values were obtained from the students' academic records--these values are in a scale from 0 to 40 points. After obtaining the attributes, we proceeded to analyze them and calculate their correlation. For this purpose, the Pearson's Correlation Coefficient (\(R\)) was calculated, which is independent of the variables' scale of measurement. Table 2 presents these correlation values, where those with a significance \(p\) less than 0.1 were placed in highlighted text. We can see that there is a significant correlation between the attributes \(\Delta t_{P}\) and _ATU_ with _GPA1B_. This reflects that students who remain at university for a time equal or greater than the time registered according their schedules, obtain a better result in their academic performance. This correlation can be better observed in Figure 5, where the attributes _GPA1B_ and \(\Delta t_{P}\) of each student are depicted. We can see a higher percentage of student attendance helps to improve academic performance. Regarding the other attributes measured with the ISABELA application, we found a strong correlation with the students' performance. However, the grades point average obtained in the first bimester (_GPA1B_) have a significant correlation with the historical academic values of _CGPA_ (\(R\) = 0.576) and _API_ (\(R\) = 0.563). The historic academic values can be used as good attributes in the prediction of students' academic performance. On the other hand, we can distinguish strong relationships between certain attributes collected by the application through sensors and the daily questionnaire, as we can see, for example, in the correlation (\(R\) = 0.627) with number of Bluetooth devices (\(ND\)) near to student and the percentage of sociability calculated (\(\%S\)).