Table 2.

Fuzzy scale

Fuzzy number	Linguistic variables	Membership function
$\tilde{1}$	Preferred-equally	(1, 1, 1)
$\tilde{3}$	Preferred-moderately	(2/3, 1, 3/2)
$\tilde{5}$	Preferred-strongly	(3/2, 2, 5/2)
$\tilde{7}$	Preferred-very strongly	(5/2, 3, 7/2)
$\tilde{9}$	Preferred-extremely	(7/2, 4, 9/2)