Encode variables

Real values

X1

X2

X1

X2

Factorial trials

−1

−1

58.66

68.78

1

−1

76.34

68.78

−1

1

58.66

111.22

1

1

76.34

111.22

Star trials

−1.41

0

55.00

90.00

1.41

0

80.00

90.00

0

−1.41

67.50

60.00

0

1.41

67.50

120.00

Centre trials

0

0

67.50

90.00

0

0

67.50

90.00

0

0

67.50

90.00

0

0

67.50

90.00

0

0

67.50

90.00