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.