Project 14: Findings on how the response variable, paint coat
thickness, depends on four input factors.

Col 1: belt speed.
Col 2: tube width.
Col 3: pump pressure.
Col 4: paint viscosity.
Cols 5,6: Thickness of paint coat (in mm).

-1.5  -2  -2  -2    1.51  1.18
 0.5  -2  -2  -2    0.64  0.78
-1.5   0   0  -2    1.74  1.98
 0.5   0   0  -2    1.33  1.06
-1.5  -2   0   0    1.71  1.60
 0.5  -2   0   0    1.15  1.29
-1.5   0  -2   0    1.71  1.61
 0.5   0  -2   0    0.91  1.30