2.5. Statistical analysis The results were expressed as mean ฑ standard deviation of means. The coefficient of variation was calculated as the standard deviation divided by the mean. Data were analyzed with ANOVA procedures. Post hoc analysis was performed by using the Tukey’s test to find means that are significantly different from each other. The significance level assumed was 0.05. Statistica for Windows (Statsoft Inc., Tulsa, USA) was used in all data analyses.