Modeling Antimicrobial Activity of Clorox Using an Agar-Diffusion Test: A New Twist on an Old Experiment

The computer statistical software package Minitab is used to model sensitivity of several microbes to the disinfectant NaOCl (Clorox) utilizing the Kirby-Bauer technique. Each group of students collects data for one microbe, conducts regression analyses (e.g. linear, quadratic and cubic), and then chooses the best-fit model based upon the highest r-value obtained. This experiment provides an opportunity to improve critical thinking skills of students by allowing them to determine which best-fit model is both mathematically and biologically acceptable.