A total of 260 questionnaires were completed.
Descriptive statistics and histograms were employed to illustrate
the interviewees' characteristics, their responses, as well as
possible differences between sites or groups of people. Whenever
needed chi-squared tests provided significance levels for the observed
differences. The relationship between the various perception
variables and the implied causative environmental parameters was
investigated using Pearson correlation coefficients. All the coeffi-
cients reported in the following sections are significant at the
0.05 level or better. The effect of confounding parameters was also
investigated using partial correlation coefficients and cross-tabs, as
well as chi-squared tests against equiprobability. Finally, ordinal
regression based on a logit probability model, was used to quantify
the relevance of the various parameters with respect to the