2.3 Statistical analysis
Data were analyzed with IBM SPSS Statistics for Windows version 25.0 (IBM Corp.,Armonk, NY, USA). The null hypothesis was that no statistical difference in vascularization-patterns in both oral and nasal mucosa existed between the two groups. The results of Sniffin’ sticks have also been compared. For statistical analysis, if an EGM-threshold could not be measured at all, then it was assigned a numerical value of 36 dB. To examine if our results were normally distributed, we applied a quantile-quantile plot (QQ plot), which proved that the distribution was not normal. As a result, non-parametric tests were applied. The level of statistical significance was set at p < 0.05. On each occasion, the findings between two groups were compared by using Kruskal-Wallis and Mann-Whitney tests. The Bonferroni correction was applied when necessary. Tukey’s multiple comparison was used to detect differences significant at the 0.05-level in mean thresholds for both groups.