Table 3.

Linguistic conversion scale and their corresponding PHFEs

Linguistic term	Numerical values with PHFEs
Exceptional	{〈0.8, 0.5〉,〈1.0, 0.5〉}
Very good	{〈0.7, 0.6〉,〈0.8, 0.4〉 }
Satisfactory	{〈0.5, 0.4〉,〈0.7, 0.6〉}
Average	{〈0.3, 0.7〉,〈0.5, 0.3〉}
Insufficient	{〈0.1, 0.8〉,〈0.3, 0.2〉}