At 04:09 PM 03/04/98 -0800, Steven X. Schwenk wrote:
>
>Ian...I know nothing as far as whether the variables I have proposed are
>appropriate or sufficient for meaningful statistical analysis.

All that matters is that they can be quantified in some way.  Best is
actual ratio data, measured on a scale with equal intervals and a zero
point, but anything that can be quantified will do, even if the scale is
arbitrary.  Hardness of water, for instance, could be measured on a scale
of 1 to 10, where 1 is distilled water and 10 is water from the Great Salt
Lake.  Or dichotomous measures can be used (yes or no, present or absent).