## 4 Experimental Results and Discussion
### Results and Discussion
#### 4.3.3 Interaction Latency  
The interaction latency was measured when the proposed method was applied and when it was not. The former means time from the moment when the virtual object for interaction appears to the moment when the prediction is completed by the proposed method. The latter means time from the moment when the virtual object for interaction appears to the moment when the interaction with the virtual object is really performed. The comparison result of the average interaction latency for each subject is shown in Figure 11. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Trial No.**} & \multicolumn{8}{c}{**No. of Successful Predictions**} \\ \cline{2-13}  & \multicolumn{2}{c}{**Subject 1**} & \multicolumn{2}{c}{**Subject 2**} & \multicolumn{2}{c}{**Subject 3**} & \multicolumn{2}{c}{**Subject 4**} & \multicolumn{2}{c}{**Subject 5**} & \multicolumn{2}{c}{**Subject 6**} & \multicolumn{2}{c}{**Subject 7**} \\ \cline{2-13}  & **FP** & **FN** & **FP** & **FN** & **FP** & **FN** & **FP** & **FN** & **FP** & **FN** & **FP** & **FN** & **FP** & **FN** \\ \hline
2 & 0 & 1 & 0 & 8 & 0 & 1 & 2 & 2 & 0 & 0 & 1 & 1 & 0 & 0 \\
4 & 0 & 2 & 1 & 4 & 0 & 0 & 1 & 2 & 0 & 0 & 1 & 3 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Number of false positives (FP) and false negatives (FN): pinch. Figure 10: The average number of interaction predictions, with respect to gesture, for each subject. The red arrows in Figure 11 show the reduction of interaction latency by applying the proposed method. To confirm more precisely whether the time differences, such as the red arrows, are significant, a paired-sample \(t\)-test was performed for the average interaction latency with respect to the subject. Table 14 shows the results of the normality test to perform the paired-sample \(t\)-test. As a result of the normality test, as shown in Table 14, the significance level (red boxes in Table 14) of both the Kolmogorov-Smirnov and the Shapiro-Wilk test was greater than 0.05, so the average interaction latency data satisfy the normal distribution. Since the measured data satisfy the normal distribution, a paired-sample \(t\)-test was performed, and the result is shown in Tables 15 and 16. As a result of the paired-sample \(t\)-test, as shown in Table 15, it was confirmed that the interaction latency (red box in Table 15) in the 'With proposed method' case (1.3815 s) was further reduced, compared to the 'Without proposed method' case (1.5718 s). The significance level (red box in Table 16) of the paired-sample \(t\)-test was less than 0.05, so the null hypothesis of the paired-sample \(t\)-test was rejected. Therefore, from the above results, it was confirmed that the interaction latency was significantly reduced (by \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Paired Differences**} & \multirow{2}{*}{**t**} & \multirow{2}{*}{**df**} & \multirow{2}{*}{**Sig.** (2-Tailed)} \\ \cline{2-2} \cline{5-7}  & **Mean** & & & & & & \\ \hline With proposed method & \(-\)0.19025 & 0.05524 & 0.02088 & \(-\)0.24134 & \(-\)0.13916 & \(-\)9.1125 & 0.000 \\ \hline \hline \end{tabular}  
* A 95% confidence interval of the difference.  
\end{table} 
Table 16: Results of the paired-sample \(t\)-test for average interaction latency for each subject: paired differences. Figure 11: Comparison of the average interaction latency (with/without the proposed method) for each subject. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**[PERSON]–Smirnov 1**} & \multicolumn{3}{c}{**[PERSON]–[PERSON]**} \\ \cline{2-7}  & **Statistic** & **df** & **Sig.** & **Statistic** & **df** & **Sig.** \\ \hline With proposed method & 0.193 & 7 & 0.200 * & 0.926 & 7 & 0.514 \\ Without proposed method & 0.167 & 7 & 0.200 * & 0.949 & 7 & 0.719 \\ \hline \hline \end{tabular}  
* This is a lower bound of the true significance.1 Lilliefors Significance Correction.  
\end{table}