## 3 Results
### Statistical Analysis Results--Radial Tire  
Table 8 presents the results of the multivariate analysis of variance for the results obtained for the radial tires. Similarly to the previous case, \(p\)-values indicate the level of probability of accepting the null hypothesis that states there is no significant impact of the factor on the analyzed parameter.  
In analyzing the data presented in the table above, it can be concluded that the tire inflation pressure had a significant impact on all analyzed parameters. In the case of the second factor (vertical load of the wheel), there was no significant effect on the depth of the generated footprint (the significance was maintained in the remaining analyzed parameters). Moreover, based on the results of post hoc tests ([PERSON]'s HSD), it was found  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Footprint Parameter** & **Factor** & **Factor Level** & **Arithmetic Mean** & \(\pm\)**SD** & \(p\)**-Value** \\ \hline \multirow{4}{*}{Width of the footprint, mm} & \multirow{2}{*}{Vertical load} & 11.8 kN & 449.15 \({}^{\text{A}}\) & 25.31 & \\ \cline{3-6}  & & 19.6 kN & 474.76 \({}^{\text{B}}\) & 6.59 & 0.000220 \\ \cline{3-6}  & & 0.08 MPa & 481.77 \({}^{\text{A}}\) & 12.61 & \\ \cline{3-6}  & & 0.16 MPa & 456.57 \({}^{\text{B}}\) & 21.13 & 0.000275 \\ \cline{3-6}  & & 0.24 MPa & 447.53 \({}^{\text{B}}\) & 21.83 & \\ \hline \multirow{4}{*}{Length of the footprint, mm} & \multirow{2}{*}{Vertical load} & 11.8 kN & 420.80 \({}^{\text{A}}\) & 36.87 & \\ \cline{3-6}  & & 19.6 kN & 496.09 \({}^{\text{B}}\) & 18.31 & \\ \cline{3-6}  & & 0.08 MPa & 497.41 \({}^{\text{A}}\) & 19.64 & \\ \cline{3-6}  & & 0.16 MPa & 454.49 \({}^{\text{B}}\) & 39.36 & 0.000007 \\ \cline{3-6}  & & 0.24 MPa & 423.45 \({}^{\text{C}}\) & 34.96 & \\ \hline \multirow{4}{*}{Depth of the footprint, mm} & \multirow{2}{*}{Vertical load} & 11.8 kN & 17.27 \({}^{\text{A}}\) & 2.65 & \\ \cline{3-6}  & & 19.6 kN & 18.88 \({}^{\text{A}}\) & 2.56 & \\ \cline{3-6}  & & 0.08 MPa & 10.21 \({}^{\text{A}}\) & 0.61 & \\ \cline{3-6}  & & 0.16 MPa & 19.66 \({}^{\text{B}}\) & 0.89 & \\ \cline{3-6}  & & 0.24 MPa & 24.36 \({}^{\text{C}}\) & 2.02 & \\ \hline \multirow{4}{*}{Cross-section area of the tire, m\({}^{2}\)} & \multirow{2}{*}{Vertical load} & 11.8 kN & 0.177 \({}^{\text{A}}\) & 0.032 & \\ \cline{3-6}  & & 19.6 kN & 0.224 \({}^{\text{B}}\) & 0.014 & \\ \cline{3-6}  & & 0.08 MPa & 0.229 \({}^{\text{A}}\) & 0.012 & \\ \cline{3-6}  & & 0.16 MPa & 0.195 \({}^{\text{B}}\) & 0.033 & \\ \cline{3-6}  & & 0.24 MPa & 0.177 \({}^{\text{C}}\) & 0.032 & \\ \hline \multirow{4}{*}{Tire–soil contact area, m\({}^{2}\)} & \multirow{2}{*}{Vertical load} & 11.8 kN & 0.207 \({}^{\text{A}}\) & 0.034 & \\ \cline{3-6}  & & 19.6 kN & 0.257 \({}^{\text{B}}\) & 0.012 & \\ \cline{3-6}  & & 0.08 MPa & 0.261 \({}^{\text{A}}\) & 0.011 & \\ \cline{3-6}  & & 0.16 MPa & 0.222 \({}^{\text{B}}\) & 0.036 & \\ \cline{3-6}  & & 0.24 MPa & 0.212 \({}^{\text{B}}\) & 0.035 & \\ \hline \end{tabular} The letters at arithmetic means (\({}^{\text{A},\text{B},\text{C}}\)) denote separate homogenous groups.  
\end{table}
Table 8: Results of the statistical analysis of experimental data for the radial tire; the significance level \(\alpha=0.05\); SD—standard deviation.  
that in the case of the impact of vertical load on the depth of footprint, both levels of the factor were classified into the same group (hence, there was no significant effect of this factor). In the case of the second factor, separate groups were found for the length of the footprint, its depth, and cross-section area; meanwhile, two homogeneous groups were found for the width of the footprint and the area of the footprint--in both cases, the inflation pressure levels of 0.16 MPa and 0.24 MPa qualified into the same group.