Table 1.

Relationship between coded and actual values of a variable.

Quality	Coded value	Actual value
Lowest	$-\alpha$	$x_{\mathit{min}}$
Low	$-1$	$\frac{x_{\mathit{max}}+x_{\mathit{min}}}{2}-\frac{x_{\mathit{max}}-x_{\mathit{min}}}{2\times 2^{q/4}}$
Centre	$0$	$\frac{x_{\mathit{max}}+x_{\mathit{min}}}{2}$
High	$+1$	$\frac{x_{\mathit{max}}+x_{\mathit{min}}}{2}+\frac{x_{\mathit{max}}-x_{\mathit{min}}}{2\times 2^{q/4}}$
Highest	$+\alpha$	$x_{\mathit{max}}$

Where $x_{\mathit{min}}$ and $x_{\mathit{max}}$ are respectively the minimum and maximum values of $x$, and $q$ is the number of variables.