*2.9. Statistical Analysis*

The assumption of homogeneity was tested using Levene's test. If the overall analysis of variance was significant and the assumption of homogeneity of variance was met, Duncan's multiple range test was performed. If the assumption of homogeneity of variance was not met, Dunnett's T3 test was used as the post hoc test. In nonparametric multiple analysis, the Kruskal–Wallis H-test was adopted. If a statistically significant di fference was observed between groups, the Mann–Whitney U-test was used to identify the groups. SPSS Statistics 18.0K (IBM Corp., Armonk, NY, USA) was used for all statistical analysis and the level of significance was set at *p* < 0.05.
