Table 4: Chen’s fuzzy scale.

Linguistic variableFuzzy scale

Very low (VL)(0, 0, 0.1)
Low (L)(0, 0.1, 0.3)
Medium low (ML)(0.1, 0.3, 0.5)
Medium (M)(0.3, 0.5, 0.7)
Medium high (MH)(0.5, 0.7, 0.9)
High (H)(0.7, 0.9, 1)
Very high (VH)(0.9, 1, 1)