Data analysis consisted of several steps. In
the first step, the normal distribution of the
results in the populations was tested using a
Shapiro-Wilk test. When p values were higher
than 0.05, the distribution was considered
normal and the next step was to test the equality
of group variances using a Brown-Forsyth
test. If it resulted in p values higher than 0.05,
the variances were considered as equal. In this
case, to compare groups of means, an analysis
of variance (F-test) was applied along with Duncan’s
test to distinguish significant differences.
Duncan’s test was conducted only if an Ftest
resulted in p values lower than 0.05. If the
distribution of the data was different from normal
or the groups of variances were not equal,
a non-parametric Kruskal-Wallis test was used.
All analyses were conducted in Statistica 8.0