## 3 Model Development and Validation
### Data Analysis
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Different Backrest Angles**} \\
**Parameters** & **100–110\({}^{\circ}\)** & **100–120\({}^{\circ}\)** & **110–120\({}^{\circ}\)** \\ \cline{2-6}  & **Z** & **Sig** & **Z** & **Sig** & **Z** & **Sig** \\ \hline Back peak object pressure & \(-\)20.654 & \(<\)0.01 ** & \(-\)18.423 & \(<\)0.01 ** & \(-\)11.139 & \(<\)0.01 ** \\ Back peak contact pressure & \(-\)21.092 & \(<\)0.01 ** & \(-\)21.039 & \(<\)0.01 ** & \(-\)5.643 & \(<\)0.01 ** \\ Back contact area & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** \\ Back contact pressure & \(-\)19.327 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** & \(-\)20.654 & \(<\)0.01 ** \\ Hip contact area & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** \\ Hip strength & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** & \(-\)21.222 & \(<\)0.01 ** \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Post hoc two-by-two comparison of different backrest angles at a spacing of 63 cm. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Different Backrest Angles**} & **Cardinal** & **Significance** \\ \cline{2-6}
**Parameters** & **100\({}^{\circ}\)** & **110\({}^{\circ}\)** & **120\({}^{\circ}\)** & **Values** & **(_p_)** \\ \hline Back peak object & & & & & \\ pressure & 30.71 \(\pm\) 2.15 & 32.81 \(\pm\) 1.67 & 32.03 \(\pm\) 2.16 & 588.203 & \(<\)0.01 ** \\ Back peak & & & & & \\ contact pressure & 31.13 \(\pm\) 2.13 & 33.98 \(\pm\) 2.14 & 34.55 \(\pm\) 2.05 & 798.623 & \(<\)0.01 ** \\ Back contact area & 382.03 \(\pm\) 7.98 & 411.99 \(\pm\) 11.26 & 463.28 \(\pm\) 10.87 & 1200 & \(<\)0.01 ** \\ Back contact & & 13.82 \(\pm\) 0.35 & 13.59 \(\pm\) 0.23 & 13.29 \(\pm\) 0.29 & 1014.514 & \(<\)0.01 ** \\ pressure & & & & & \\ Hip contact area & 741.99 \(\pm\) 7.76 & 718.98 \(\pm\) 6.48 & 679.19 \(\pm\) 5.52 & 1200 & \(<\)0.01 ** \\ Hip strength & 977.39 \(\pm\) 20.96 & 934.55 \(\pm\) 17.67 & 902.32 \(\pm\) 18.01 & 1200 & \(<\)0.01 ** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Pressure distribution at a spacing of 63 cm. lower the subjective comfort evaluation [35]. As shown in Table 4, a post hoc two-by-two comparison of the three backrest inclination angles at 63 cm pitch showed significant differences in peak back-contact pressure and peak hip-contact pressure at 95% confidence intervals for each of the two different angles. As shown in Table 3, the backrest is subjected to the largest contact area of 741.99 \(\pm\) 7.76 cm\({}^{2}\) at an inclination of 120\({}^{\circ}\), followed by 718.98 \(\pm\) 6.48 cm\({}^{2}\) at an inclination of 110\({}^{\circ}\) and 679.19 \(\pm\) 5.52 cm\({}^{2}\) at an inclination of 120\({}^{\circ}\). The contact area of the buttocks is the opposite of that of the back, with the largest contact area of 741.99 \(\pm\) 7.76 cm\({}^{2}\) at an inclination of 100\({}^{\circ}\), followed by 718.98 \(\pm\) 6.48 cm\({}^{2}\) at an inclination of 110\({}^{\circ}\), and 679.19 \(\pm\) 5.52 cm\({}^{2}\) at an inclination of 120\({}^{\circ}\). The contact area is the total area of the back or buttocks in contact with the support, and the size of this area can be used to measure the extent and condition of the body part that is in contact. Generally speaking, the larger the contact area, the lower the local pressure on the back and the better the fit of the hips to the seat. This means that the corresponding average pressure will be smaller, and comfort will be increased when using certain seat materials. However, under actual flight conditions, a too-large backrest inclination angle will affect the view angle when driving, so usually the backrest inclination angle is not too large. As shown in Table 4, a two-by-two post hoc comparison of the three backrest inclination angles at 63 cm showed significant differences in back contact area and hips at the 95% confidence interval for each of the two different angles.