Correlation of fuzzy sets

When we deal with crisp data, it is very common to find the correlation bet ween variables. Here, we propose a method to calculate the correlation coef ficient for fuzzy data, but rather than defining the correlation on the int uitionistic fuzzy sets like most of the previous works, we adopt the method from mathematical statistics. The value computed from our formula not only provides us the strength of the relationship of fuzzy sets, but also shows that the fuzzy sets are positively or negatively correlated. (C) 1999 Else vier Science B.V. All rights reserved.