The data are from the first 8 rows of the pollutant water treatment example in the book by Box, Hunter and Hunter, 2nd edition, Chapter 5, Question 19.

The 3 factors (C, T, and S) are in coded units where: C: -1 is chemical brand A; +1 is chemical brand B T: -1 is 72F for treatment temperature; +1 is 100F for the temperature S: -1 is No stirring; +1 is with fast stirring

The outcome variable is: y: the pollutant amount in the discharge [lb/day].

The aim is to find treatment conditions that MINIMIZE the amount of pollutant discharged each day, where the limit is 10 lb/day.

`data(pollutant)`

A data.frame containing 8 observations of 4 variables (C, S, T and y)

Box, G. E. P. and Hunter, J. S. and Hunter, W. G., 2005, *Statistics for
Experimenters*, Second edition. Wiley.