For all data, the homogeneity of variance was tested by Bartlett’s Test. If this test indicated no homogeneity of variance the transformed, values were used for analysis of variance. If still no homogeneity of variance was obtained by the transformation was cancelled and the statistical analysis should be treated with caution.
Assessment data were than analyzed using a two-way analysis of variance (ANOVA) on untransformed and transformed data. The probability of no significance differences occurring between treatment means is calculated as the F probability value (p(F).
A mean comparison test was only performed when the treatment probability of F that is calculated during analysis of variance was significant at the observed significance level specified for the mean comparison test. The mean separation letter ‘’ a‘’ is assigned to each treatment mean in an assessment data column when a non-significant treatment P (F) is detected
Student Newn-Keuls’ multiple comparison test was applied to separate any treatment difference that may be implied by the ANOVA TEST and these are indicated by a letter test; treatment means with no letters in common are significantly difference according to the test initiated at the 95% confidence level.