## 4 Results
### Workload  
Given that NASA-TLX is commonly used to compare results between tasks, we used this survey to evaluate the differences between the three systems. In this survey, a lower score indicated less workload and effort, which translated to better results. The averages are presented in Figure 3. Starting with the mental demand, [PERSON] had the least demand, followed closely by [PERSON] and then the eye gaze interaction, which showed a significant difference to the other two. In terms of the physical demand, [PERSON] scored the lowest,  
Figure 1: Eye tracker control bar. The text on the buttons appearing on the screen are as follows, starting from the first line, first button on the left: Light, Music, Weather, News, and Call. Figure 2: Selecting a command. The text on the buttons appearing on the screen are as follows, starting from the first line, first button on the left: Light, Music, Weather, News, and Call. followed by Daria, which had only a slight difference. However, the eye gaze interaction imposed a notably higher level of demand. For the temporal demand, the pattern was similar to that of the mental demand: [PERSON] scored the lowest, followed by [PERSON] and then the eye gaze interaction. In terms of the performance, which is how successful the user was in accomplishing what they were asked to do, [PERSON] had the lowest score, then [PERSON], showing a marginal difference, and the eye gaze interaction, which had a significantly higher level of demand. Finally, considering the effort and frustration, [PERSON] had the lowest score, followed by [PERSON] and then the eye gaze interaction. Similar to the statistical analysis for the SUS, the Friedman test was used to determine whether there were statistically significant differences in the workload scores across the three interaction methods (see Table 2). The test revealed statistically significant differences in the physical demand (\(p\) = 0.003), performance (\(p\) = 0.040), and effort (\(p\) = 0.011) whereas no significant differences were found for the mental demand (\(p\) = 0.174), temporal demand (\(p\) = 0.054), and frustration (\(p\) = 0.244). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Category** & **System** & **Mean Rank** & **Chi-Square** & \(p\)**-Value** & \(p\)**-Value Assessment** \\ \hline \multirow{3}{*}{Mental demand} & Daria & 2.25 & & & \\  & Eyegaze & 1.63 & 3.50 & 0.174 & Not Significant \\  & Alexa & 2.13 & & & \\ \hline \multirow{3}{*}{Physical demand} & Daria & 2.31 & & & \\  & Eyegaze & 1.25 & 11.47 & 0.003 & **Significant** \\  & Alexa & 2.44 & & & \\ \hline \multirow{3}{*}{Temporal demand} & Daria & 2.44 & & & \\  & Eyegaze & 1.38 & 5.85 & 0.054 & Not Significant \\  & Alexa & 2.19 & & & \\ \hline \multirow{3}{*}{Performance} & Daria & 2.31 & & & \\  & Eyegaze & 1.44 & 6.42 & 0.040 & **Significant** \\  & [PERSON] & 2.25 & & & \\ \hline \multirow{3}{*}{Effort} & [PERSON] & 2.50 & & & \\  & Eyegaze & 1.25 & 8.96 & 0.011 & **Significant** \\  & Alexa & 2.25 & & & \\ \hline \multirow{3}{*}{Frustration} & [PERSON] & 2.38 & & & \\  & Eyegaze & 1.69 & 2.82 & 0.244 & Not Significant \\ \cline{1-1}  & [PERSON] & 1.94 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Workload—significance between the three interaction systems. [PERSON]’s ANOVA was used for overall comparison. The significance level is 0.05. Figure 3: NASA-TLX workload. To understand the specific differences between each pair of methods, we conducted a Wilcoxon test for the categories that had significant Friedman results (see Table 3). For the physical demand, the pairwise comparison showed significant differences in favor of Alexa over the eye gaze interaction (\(p=0.024\)) and Daria over the eye gaze interaction (\(p=0.025\)), indicating that Daria and Alexa required less physical effort than the eye gaze method. Similarly, for the temporal demand, significant differences were noted between Daria and the eye gaze interaction (\(p=0.020\)), in which Daria required less time to perform tasks.