## 3 Materials and Methods
### Survey Overview and Reliability
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Block** & **Variable Name** & **Question** \\ \hline \multirow{4}{*}{**Socio-demographic**} & SD1 & Age \\  & SD2 & Gender \\  & SD3 & Highest university year \\  & SD4 & First time enrolling on the DM \\ \hline \multirow{4}{*}{**Ease of use and friendliness**} & E1 & Is MaGraDa easy to use? \\  & E2 & Is MaGraDa easy to learn? \\  & E3 & Is the MaGraDa interface \\  & E3 & Eleasant? \\  & E4 & Are the menus of MaGraDa \\  & E5 & well-structured? \\  & E5 & Is the graphic mode of MaGraDa \\  & & intuitive? \\ \hline \multirow{4}{*}{**Content**} & C1 & Is the information provided by \\  & C1 & MaGraDa about procedures and \\  & & algorithms clear? \\  & C2 & Is the information provided by \\  & C3 & Is the information provided by \\  & & MaGraDa well-organised? \\  & C4 & Does MaGraDa provide all the \\  & C4 & functionalities and capabilities \\  & & you expect it to have? \\ \hline \multirow{4}{*}{**Didactic level**} & D1 & Does the information provided by \\  & D1 & MaGraDa help you understand \\  & & the concepts of graphs? \\  & D2 & Does MaGraDa facilitate your \\  & & independent work? \\  & & Does MaGraDa help you identify, \\  & & diagnose, and correct errors in \\  & & your graph exercises? \\  & & Does MaGraDa assist you in \\  & & terms of your academic \\  & & performance? \\  & & Would you prefer to use \\  & & MaGraDa for this subject rather \\  & & than doing the exercises without \\  & & computer assistance? \\  & & Do you believe that MaGraDa will \\  & & help you achieve a better exam \\  & & grade? \\ \hline \multirow{4}{*}{**General opinion**} & G1 & Would you recommend using \\  & G1 & MaGraDa for learning concepts \\  & & related to graphs? \\  & & Do you consider that using \\  & & MaGraDa makes learning about \\  & & graphs more interesting? \\  & & Overall, are you satisfied with the \\  & & MaGraDa software? \\ \hline \multirow{2}{*}{**Comments and suggestions**} & CS & Add any comments or \\  & & suggestions about MaGraDa \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Questions contained in the survey. correlation coefficients of between 0.501 and 0.586. To enable us to explore, understand, and interpret the relationships between these variables, dimensionality reduction techniques were applied [52; 53]. To assess the reliability of the measuring instrument, [PERSON]'s alpha [54] was used. The reliability refers to the degree of internal consistency of the questionnaire and scale [55]. For all items combined, a value of 0.894 was found for Cronbach's alpha (see Table 4), indicating a high level of internal consistency. The values obtained for the sets E, C, D and G of grouped items were 0.763, 0.709, 0.805 and 0.838, respectively. Table 5 summarises the statistics of the questionnaire as a whole and shows the values of Cronbach's alpha coefficient when each item is removed. It can be observed that when item E5 is removed, the overall reliability is 0.898. However, a decision was made to keep this item because it does not significantly affect the reliability of the instrument and is a priori relevant when evaluating the user-friendliness of MaGraDa.