Cryoprotectant

Symbol

Variable values at each level of each variable and code

Unencoded

Coded

−1.682

−1

0

+1

+1.682

Skim milk

X1

x1

5%

9.06%

15%

24.06%

25%

Sucrose

X2

x2

1%

2.22%

4%

6.22%

7%

Trehalose

X3

x3

0%

1.62%

4%

5.63%

8%