All data were previously checked for normality using the Kolmogorov–Smirnov test and for homogeneity of variances using the Levene’s test (Zar, 1996). Data not meeting these criteria were transformed appropriately (Zar, 1996) and checked again for normality and homocedasticity. Whenever data did not meet those criteria,
non- parametric tests (Kruskal–Wallis test) were applied. These analyses were performed in the Minitab 16 software package.