# A New Training Method for VR Sickness Reduction
## 3 Results
### VR Sickness Response  
To confirm the normality of the VR sickness response, the Shapiro-Wilk test was conducted. The test results confirmed non-normality. Therefore, the Wilcoxon signed-rank test was used in the analysis to compare the mean VR sickness response scores pre- and post-experiment. Considering the two subjects who did not complete the pre- and post-experiment sessions, the VR sickness response scores were used as the input per minute. As a result of the comparison, the VR sickness response decreased by 31.03% in the post-experiment stage compared to the pre-experiment stage, but this difference was not statistically significant. Table 7 shows the pre-experiment and post-experiment VR sickness response results, respectively. Additionally, the subjects were divided into an increase group and a decrease group to analyze trends. Out of the total of 13 subjects, 2 maintained their VR sickness responses, 7 showed an increase, and 4 showed a decrease. The pre-experiment VR sickness response averaged 1.34 times for the decrease group and 0.31 times for the increase group. The mean change from the pre- to the post-experiment stage of the decrease group was 0.76 times, while that of the increase group was 0.11 times. The visualization of VR sickness responses divided into the increase and decrease groups (Figure 8) revealed that the increase group showed little difference pre- and post-experiment, while the decrease group demonstrated a large reduction in VR sickness response through the training. This means that subjects who frequently experienced VR sickness experienced less VR sickness through the proposed training.  
We compared the viewing times of the experimental content between the pre- and post-experiment sessions for the two subjects who were unable to watch the content until the end due to VR sickness. In the pre-experiment session, the first subject watched for 16 min and the second subject watched for 10 min. In the post-experiment session, both subjects watched the VR content for 25 min. The VR content viewing time of the first subject increased by 9 min, and the viewing time of the second subject increased by 15 min. The difference in viewing times for the subjects who dropped out are shown in Table 8.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Disorientation (D)**} & \multicolumn{3}{c}{**Total Score (T)**} \\ \cline{2-7}
**Subject** & \begin{tabular}{c} **Pre-** \\ **Experiment** \\ \end{tabular} & \begin{tabular}{c} **Post-** \\ **Experiment** \\ \end{tabular} & \begin{tabular}{c} **Increase/** \\ **Decrease** \\ \end{tabular} & \begin{tabular}{c} **Pre-** \\ **Experiment** \\ \end{tabular} & \
\begin{tabular}{c} **Post-** \\ **Experiment** \\ \end{tabular} &
\begin{tabular}{c} **Increase/** \\ **Decrease** \\ \end{tabular} \\ \hline S1 & 125.28 & 167.04 & Increase & 1244.22 & 1229.33 & Decrease \\ S2 & 27.84 & 27.84 & Maintain & 224.84 & 367.56 & Increase \\ S3 & 0.00 & 41.76 & Increase & 120.72 & 241.23 & Increase \\ S4 & 41.76 & 0.00 & Decrease & 525.69 & 269.80 & Decrease \\ S5 & 27.84 & 41.76 & Increase & 260.52 & 297.92 & Increase \\ S6 & 13.92 & 13.92 & Maintain & 137.10 & 137.10 & Maintain \\ S7 & 41.76 & 27.84 & Decrease & 383.94 & 288.87 & Decrease \\ S8 & 0.00 & 27.84 & Increase & 56.69 & 104.12 & Increase \\ S9 & 0.00 & 0.00 & Maintain & 92.37 & 0.00 & Decrease \\ S10 & 0.00 & 0.00 & Maintain & 56.69 & 35.67 & Decrease \\ S11 & 69.60 & 27.84 & Decrease & 494.42 & 196.49 & Decrease \\ S12 & 55.68 & 83.52 & Increase & 606.10 & 525.47 & Decrease \\ S13 & 222.72 & 41.76 & Decrease & 1765.05 & 340.93 & Decrease \\ \hline \hline \end{tabular}
\end{table}
Table 6: The results of the increase or decrease by subjects: disorientation and total score.