## 3 Results
### Joystick  
#### 3.2.1 Identification of Significant Factors Influencing the Evaluation Parameters  
Table 8 shows a comparison of the factors and evaluation parameters, including the significance values calculated by ANOVA for the joystick analyses. At least one factor had a significant influence (\(p<0.05\)) on the evaluation parameters _time on task_ (IoT) and _positioning accuracy_ (Acc. ), _presence_ (SUSQ), _perspicuity_ (UEQ\({}_{\text{P}}\)), _efficiency_ (UEQ\({}_{\text{E}}\)), _stimulation_ (UEQs), and _novelty_ (UEQ\({}_{\text{N}}\)) of the User Experience Questionnaire. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameter** & **Pred. Mean** & **Std Dev** & **95\% PI Low** & **Data Mean** & **95\% PI High** \\ \hline Time on Task & 20 s & 10 s & 7 s & 18 s & 34 s \\ Pos. Accuracy & 3.13 & 1.99 & 0.80 & 1.28 & 5.47 \\ SUSQ & 4.90 & 1.21 & 3.39 & 4.50 & 6.42 \\ NASA & 0.00 & 1.50 & \(-\)3.08 & 2.63 & 2.12 \\ UEQ\({}_{\text{P}}\) & 2.96 & 0.37 & 2.49 & 2.06 & 3.43 \\ UEQ\({}_{\text{E}}\) & 2.43 & 0.46 & 1.72 & 1.88 & 3.15 \\ UEQ\({}_{\text{D}}\) & 2.42 & 0.72 & 1.46 & 2.13 & 3.38 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Results of confirmation runs for the rotary control. Predicted parameter results vs. measured results of the validation runs. Figure 5: Optimized shape and diameter of the rotary control. Figure 6 shows the effect of the factor positioning speed on the evaluation parameters _time on task_ (ToT) and _positioning accuracy_ (Acc.). The figure shows that the test participants with a high rate of change needed, on average, 64 s less to complete the tasks than the test participants with a low rate of change. A higher change rate had the opposite effect on positioning accuracy. The higher the positioning speed, the more errors the test participants made. Table 9 lists the mathematical models for the calculation of the evaluation parameters, including the adjusted coefficient of determination (R\({}^{2}\)\({}_{Adj}\)) and SNR for the examination of the joystick. The critical Cook's distance was not exceeded in any of the tests. \begin{table}
\begin{tabular}{c c c c c c c} \hline F & **ToT** & **Acc** & **SUSQ** & **UEQ\({}_{P}\)** & **UEQ\({}_{E}\)** & **UEQ\({}_{S}\)** & **UEQ\({}_{N}\)** \\ \hline A & \textless{}0.001 & \textless{}0.001 & — & — & \textless{}0.001 & 0.016 & — \\ B & — & — & — & — & — & — & — \\ C & \textless{}0.001 & — & — & — & — & — & — \\ D & 0.014 & 0.010 & — & — & — & 0.028 & — \\ E & — & — & — & 0.014 & — & — & — \\ F & — & — & — & — & — & — & — \\ G & — & — & — & — & — & — & 0.031 \\ H & — & — & — & — & — & — & — \\ J & — & — & — & — & — & — & — \\ K & — & — & 0.008 & — & 0.039 & — & — \\ L & — & — & — & — & — & — & — \\ M & — & — & — & — & 0.007 & 0.004 & \textless{}0.001 \\ EK & — & 0.003 & — & — & — & — & — \\ AG & — & — & \textless{}0.001 & — & — & — & — \\ FL & — & — & — & — & — & — & 0.002 \\ BC & — & — & — & — & — & 0.009 & — & — \\ \hline \end{tabular}
\end{table} 
Table 8: Factors that had a significant effect (\(p<0.05\)) on the evaluation parameters when operating the joystick. If a factor had a significant influence on an evaluation parameter, the significance value was entered. If the factor has no significant influence, “—” was entered. Figure 6: Effect of the factor positioning speed on time on task and positioning accuracy. With the medium joystic size, the test participants needed the least amount of time to complete the tasks (\(\text{ToT}_{\text{medium}}=59.8\) s). With the small and large versions, the test participants needed more time (\(\text{ToT}_{\text{small}}=78.8\) s; \(\text{ToT}_{\text{large}}=87.6\) s). Test participants who operated the joystick while standing needed on average 13.6 s more time and made about 10 more errors than test participants who were seated. With acoustic feedback, the test participants perceived a higher level of presence (\(\text{SUSQ}_{\text{no acc feedback}}=3.9\)) than without it (\(\text{SUSQ}_{\text{acc feedback}}=5.0\)).