# A Comparative Study of Design Evaluation with Virtual Prototypes Versus a Physical Product
## 3 Results and Discussion
### Usability Aspects  
* Cleaning Accuracy: The correct-hit rates of the physical and virtual groups were 80% and 86%, respectively (see Table 3a,b). Interestingly, the virtual group performed better in this task. Emotional responses: The two groups were significantly different in the valence and arousal constructs (Table 3c). The physical group was in a more positive and aroused state, while the virtual group was in a more negative and passive state. * Recharging Accuracy: Both groups achieved high correct-hit rates (physical: 98%, virtual: 96%) as shown in Table 4a,b, respectively. Recharging appeared to be a well-designed operating feature and easy for the participants to execute. Emotional responses: The physical group was in a more positive and aroused state. The virtual group was in a more negative and passive state. The two groups had significant differences with regard to the valence and arousal constructs (see Table 4c). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{3}{c}{(**a**)} \\ \hline
**Option** & **Number of Times** & **\%** & **\%** \\ \hline correct & 40 & 80.0 & \\ incorrect & 10 & 20.0 & \\ total & 50 & 100.0 & \\ \hline \multicolumn{5}{c}{(**b**)} \\ \hline
**Option** & **Number of Times** & **\%** & **\%** \\ \hline correct & 43 & 86.0 & \\ incorrect & 7 & 14.0 & \\ total & 50 & 100.0 & \\ \hline \multicolumn{5}{c}{(**c**)} \\ \hline  & & **SS** & **DF** & **MS** & **F** & **P** \\ \hline \multirow{3}{*}{Correct-hit} & Between Groups & 0.040 & 1 & 0.040 & 0.135 & 0.714 \\  & Within Groups & 29.120 & 98 & 0.297 & \\  & Total & 29.160 & 99 & & \\ \hline \multirow{3}{*}{Valence} & Between Groups & 100.000 & 1 & 100.000 & 28.229 & 0.000 \\  & Within Groups & 347.160 & 98 & 3.542 & \\  & Total & 447.160 & 99 & & \\ \hline \multirow{3}{*}{Arousal} & Between Groups & 60.840 & 1 & 60.840 & 19.644 & 0.000 \\  & Within Groups & 303.520 & 98 & 3.097 & \\ \cline{1-1}  & Total & 364.360 & 99 & & \\ \hline \multirow{3}{*}{Dominance} & Between Groups & 0.010 & 1 & 0.010 & 0.002 & 0.961 \\ \cline{1-1}  & Within Groups & 416.900 & 98 & 4.254 & \\ \cline{1-1}  & Total & 416.910 & 99 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: (**a**) Usability assessment of the cleaning task with the physical product. (**b**) Usability assessment of the cleaning task with the virtual prototype. (**c**) ANOVA for usability assessment of the cleaning task. * Time setup Accuracy: The participants were requested to set the time to Wednesday, 4:05 AM. The correct-hit rate of the physical and virtual groups was 96% and 86%, respectively. Emotional responses: The two groups had no significant differences in their emotional states. * Dirt-offloading Accuracy: The virtual group achieved a higher correct-hit rate of 62% than the physical group's rate of 58% (see Table 5a,b). This could have been caused by the mechanism of the physical product requiring more manual work. However, for the virtual prototypes, a simple clicking action could accomplish the same task. Emotional responses: The two groups reacted differently with regard to the valence and arousal constructs (see Table 5c). The physical group was in a more positive and aroused state, while the virtual group was in a more negative and passive state.