I got an example from this book on page 318:
Chemometrics for Pattern Recognition By Richard G. Brereton. The example explained that;
classes A and B are more often mistaken for each other than they are for classes C and D,..., as they may be more closely related or even can be better viewed as one single group.
Given a confusion matrix and assign some values to each class. How do you know which classes get confused with each other the most? Also, what it means by closely related or eve can be better viewed as one single group? How are A and B closely related and viewed as one single group in this example? Based on the value in the confusion matrix?