Name and designation of factors

Change surfaces

Change interval

−1

0

+1

Percentage of wool fiber in the mixture (percent)

x₁

50 (50/50)

60 (40/60)

70 (70/30)

10

Thickness (mm)

x₂

1.4

1.8

2.2

0.4

Surface density (gr/m²)

x₃

185

215

275

60