## 3 Results  
To test for intra-observer measurement error, all specimens were landmarked two times (an original set and a replica set) by the same observer and results were combined into a single set (called Error set in Table 1). A Multivariate Procrustes ANOVA between the dependent variable of error set and the independent factors of replica and individual was performed. Results show significant differences among individuals, a non-significant difference among replicas, and a non-significant interaction between replicas and individuals, thus indicating that there is no significant difference between replicas of the same individuals (Table 1). After verifying that there were no significant differences among sets of replicas, a single set (the replica set) was chosen at random and used for the following analysis. Results start by exploring any potential differences in septal deviation within the sample. Figure 4 shows differences in values of septal deviation distribution between males (light blue in the graph) and females (in orange). Negative values indicate left septal deviations, while positive values indicate right septal deviation. The plot shows a clear bimodal distribution for both the male and the female sample, with similar values of left and right septal deviations. Moreover, it is evident that the left deviation is more frequent in both males and females. A Kolmogorov-Smirnov test (KS test) for non-parametric distributions was performed to test for differences in septal deviation in the distribution of the male and female sample, considering the relative (to the side) and absolute (therefore the overall magnitude) values of septal deviation (Tables 2 and 3). Both table results indicate no significant difference between the male and female sample for values of septal deviation. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Error Set** & **Degrees of Freedom** & \(\mathbf{R^{2}}\) & **F** & **Z (Effect Sizes)** & \(p\)**-Value** \\ \hline
**Replica** & 1 & 0.0009 & 0.08 & \(-6.48\) & \(\sim\)1.00 \\ \hline
**Individual** & 1 & 0.026 & 2.33 & 2.16 & **0.02 \({}^{*}\)** \\ \hline
**Individual** & 1 & 0.0004 & 0.04 & \(-10.05\) & \(\sim\)1.00 \\ \hline Residuals & 88 & 0.97 & & & \\ \hline \hline Type I Sum of Squares. Sample size: 92 specimens (Error set = originals + replicas). & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Multivariate Procrustes ANOVA between the dependent variable of error set and the independent variables of individual, replica, and their interaction, to test for inter-observer error in landmarking the specimens. Asterisks indicate significance: * \(p\)-value \(\leq\) 0.05; **\(p\)-value \(\leq\) 0.01; *** \(p\)-value \(\leq\) 0.001. Figure 4: Density distribution plot showing septal deviation in males and females. Along the \(x\)-axis, negative values indicate left septal deviation; positive values indicate right septal deviation. The \(y\)-axis represents density of septal deviation values. Colours indicate female sample (**orange**) and male sample (**light blue**). Vertical dotted line indicates the zero (absence of septal deviation). Sample size: 46 specimens. To test for differences in septal deviation distribution during ontogeny (changes in age) and to identify any differences in magnitude of septal deviation in terms of side between left and right, a Multiple Linear regression between the dependent variable of septal deviation (absolute values) and the independent variables of age and deviation side (left-right) was performed (Table 4). Results of the regression show that changes in age do not have an impact on the degree of septal deviation, but that, as also evident from the plot in Figure 5, right deviations are significantly more pronounced than left ones (\(p\)-value \(<\) 0.001 ***). After analysing the septum, the results focused on its relationship with facial morphology. The analysis of facial morphology and its link to septal deviation was first investigated by dividing the overall facial variance into an asymmetric and symmetric component.