Table 1. Parametric Coded Table Used for Design of the Experiment.

factor	name	units	minimum	maximum	coded low (−1)	coded high (+1)	mean	std. dev.
A	catalyst conc	ppm	100	300	150	250	200	45.88
B	p-NP conc	ppm	50	250	100	200	150	45.88
C	pH		5	9	6	8	7	0.9177