Golfinopoulos and Arhonditsis (A-14) used a multiple regression model in a study of trihalomethanes

(THMs) in drinking water in Athens, Greece. THMs are of concern since they have been related to cancer and reproductive outcomes. The researchers found the following regression model useful in predicting THM:

The variables were as follows: chla chlorophyll concentration, pH acid/base scale, Br bromide concentration, S dummy variable for summer, Sp dummy variable for spring, T temperature, and CL chlorine concentration. The researchers reported R .52, p