## 4 Verification Based on Ergonomic Reliability Experiments  
To verify that the pull-down and hidden tool menus are important factors resulting in the different degrees of ergonomic reliability in the operation process of the three schemes, the menu on the right of Scheme B was changed to a drop-down menu, similar to Scheme A, and a hidden menu, similar to Scheme C, as illustrated in Figure 11. Thirty-three subjects who were using the software for the first time participated in the experiments. During the user's operation, an eye-tracking experiment was activated to record the observation orders of the subjects' eyes and the number of mouse clicks during the process of searching for the virtual \"save\" button. The eye-tracking serial numbers recorded by the eye movement instrument with a steady frequency based on a typical subject are also shown in Figure 11. The larger the serial number is, the longer the time the subject spent trying to find the target button. The \"save\" button of Scheme A was found by the typical subject when the eye-tracking serial number was over 50; the \"save\" button of Scheme B was found when the serial number was 18; and the target button of Scheme C was found only when the eye tracking number reached approximately 40. In Scheme A, the virtual target button was located in the drop-down menu; in Scheme B, the virtual target button was designed as a large icon on the right; and in Scheme C, the virtual target button was located in the hidden menu on the right. The data collection results of the eye-tracking serial numbers were contrasted in a one-way analysis of variance (ANOVA) based on 11 subjects that used the three schemes of the medical device software model for the first time. The \(F\) statistic was 22.15 (\(P<0.005\)), as presented in Table 2. Thus, the null hypothesis stating that the serial numbers of eye movement tracking under Schemes A, B, and C are all equal should be rejected. By contrast, the alternative hypothesis stating that the serial numbers of eye movement tracking under these three groups are not equal should be accepted. Thus, there are statistically significant differences in the serial numbers of eye tracking among the three groups. In addition, the one-premise condition of the variance analysis is that the total variance of each sample should be equal based on homogeneity of variance. [PERSON]'s test \(\chi^{2}\) was applied to test the homogeneity of variance, \(\chi^{2}\)= 1.7270 (\(P\) = 0.422). This implies that, according to the inspection standards \(\alpha\)= 0.10, the null hypothesis is not rejected, there is no statistical significance, and the three populations possess the homogeneity of variance; hence, the variance analysis applied to analyze the data is appropriate. \begin{table}
\begin{tabular}{l l l l l l} \hline \hline \multirow{2}{*}{**Source**} & **Sum of** & **Degree of** & **Mean Square** & **\(F\) Test** & **\(P\)** \\  & **Squares** & **Freedom** & **Mean Square** & **Statistic** & **Value** \\ \hline Between group & 2403.87879 & 2 & 1201.93939 & 22.15 & \textless{}0.005 \\ Within group & 1628 & 30 & 54.2666667 & & \\ Total & 4031.87879 & 32 & 125.996212 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Analysis of variance based on the serial numbers of eye tracking. Figure 11: Three different menu bars corresponding to Schemes (A–C), respectively. (**a**) Scheme A; (**b**) Scheme B; (**c**) Scheme C.  
In order to further analyze which group had the largest mean coefficient of variation and which group has the smallest mean coefficient of variation among the three groups, the Bonferroni method was applied for the multiple comparisons, as presented in Table 3. The results indicated that the button of Scheme C in the hidden menu is larger and easier to identify than that of Scheme A in the drop-down menu, which is more hidden and difficult to discover. By contrast, the button of Scheme B was the easiest to find.