Using a $2^3$ factorial design, a chemical engineer studied three factors on the yield $(y)$ of a chemical reaction. The three factors are: temperature $x_1,pH{x}_2,$ and agitation rate $x_3.$ The high and low levels of the three factors are shown in the following table:

$\backslash$table$[[,x_1(C),x_2,x_3(ra\frac{d}{m}in)$