The reliability of the collected data is validated by Cronbach’s Alpha. Cronbach's alpha is the
most common measure of internal consistency or reliability. It is most commonly used when you
have multiple Likert questions in a survey/questionnaire that form a scale and you wish to
determine if the scale is reliable (Santos, 1999). After calculating the Cronbach’s Alpha, the data
has been converted from Z-number to classical fuzzy number using the methodology provided
by Kang et al. (2012) (the methodology will be illuminated in detail in Sub-section 3.1). Then,
the classical fuzzy data set is converted into crisp data set using a common and useful
defuzzification technique known as center of gravity (Van Broekhoven and De Baets, 2006).