# 3D User Interface Design and Usability for Immersive VR
## 5 Results and Data Analysis
### Analysis of Variance (ANOVA)  
Among the different factors under evaluation, a two-way repeated ANOVA was carried out for the two independent variables:  
* The interaction modes or input device (pointer vs. controller and gesture).
* The experience (standing vs. seated).  
The following analysis shows standard deviation and means for different variables in the forms of Mvariable (e.g., Mpointer is the mean for pointer-based interaction) and SDvariable (e.g., SDstanding is the standard deviation for standing experience). Moreover, F (df, MS) is the test statistic (F-ratio) in which df and MS are the degrees of freedom and mean square, respectively, for the variables. The F-ratio was calculated using MSvariable(s)/MSerror(s) and \(p\) is the probability value. All analyses was concluded at alpha of 0.05 significance level and for 21 participants. The results are presented in Table 10.  
The null hypothesis was tested for the effect of different interaction modes on the scenario completing time using the two-way repeated ANOVA. The hypothesis here is: \"All three interaction modes will give the same interaction experience in terms of time.\" To reject the null hypothesis or not, the following conditions need to be satisfied:  
* If the F-value (F) is larger than the f critical value (Fcrit).
* If the \(p\)-value is smaller than your chosen alpha level.  
The analysis illustrates that for variable 1, the interaction modes: F (2,6556.357) = 14.613, \(p\) = 0.00000209 (Mpointer = 57.81, SDpointer = 3.08 vs. Mcontroller = 72.95, SDcontroller = 3.03 vs. Mgesture = 82.60, SDgesturer = 3.59). The \(p\)-value \(<\) alpha (0.05). This illustrates that interaction mode has a significant effect on time.  
For variable 2, the experience: F (1,408.960) = 0.911, \(p\) = 0.341 (Mstanding = 72.92, SDstanding = 3.09 vs. Mseated = 69.32, SDseated = 2.76), the \(p\)-value \(>\) alpha (0.05), which illustrates that the experience position does not have a significant effect on time.  
Moreover, the analysis shows no significant effect on time for variables 1 and 2 combined F (1,14.198) = 0.0316, \(p\) = 0.969, the \(p\)-value \(>\) alpha. Therefore, it can be concluded that interaction modes and experience did not have any combined effect on the time. Based on the above, the null hypothesis  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Tasks Given** & **Pointer–** & **Pointer–** & **Controller–** & **Controller–** & **NUI–** & **NUI–** \\  & **Standing** & **Seated** & **Standing** & **Seated** & **Standing** & **Seated** & **Standing** & **Seated** \\ \hline Avg of Task 1 & Open video 1 and play it & 9.1 & 8.4 & 15.1 & 12.6 & 12.8 & 10.8 \\ \hline Avg of Task 2 & Open folder 3 & 8.2 & 6.1 & 8.1 & 9.4 & 10.4 & 8.9 \\ \hline Avg of Task 3 & Zoom in and out all objects & 6.6 & 6.7 & 7.4 & 7.0 & 10.1 & 9.7 \\ \hline Avg of Task 4 & Duplicate folder 2 & 9.1 & 7.2 & 9.1 & 11.0 & 11.0 & 9.8 \\ \hline Avg of Task 5 & Scroll right and left & 6.1 & 5.4 & 6.7 & 6.7 & 15.9 & 11.8 \\ \hline Avg of Task 6 & Close the opened video & 7.0 & 8.2 & 11.0 & 5.8 & 9.0 & 10.5 \\ \hline Avg of Task 7 & Delete picture 4 & 9.5 & 10.0 & 13.1 & 15.4 & 11.9 & 14.8 \\ \hline Avg ofOverall Scenario & **59.4** & **56.2** & **74.3** & **71.7** & **85.0** & **80.1** \\ \hline \hline \end{tabular}
\end{table}
Table 8: Tasks and their completion time.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Interface**} & **Avg of Task 1 and Task 2 (Open a File)** & & \\ \hline Pointer–Standing & 8.6 & Average opening–Pointer & 7.9 \\ Pointer–Seated & 7.2 & & \\ \hline Controller–Standing & 11.6 & Average opening–Controller & 11.3 \\ Controller–Seated & 11.0 & & \\ \hline NUI–Standing & 11.6 & Average opening–NUI & 10.7 \\ NUI–Seated & 9.8 & & \\ \hline \hline \end{tabular}
\end{table}
Table 9: Task completion time comparison.  
is rejected meaning that interaction modes significantly affect the time taken to complete the scenario in the 3D UI.