In the case of ______________, both exclusive and inclusive class intervals can be used.

discrete variables

The correct answer is Option 2: discrete variables

Class intervals are of two types:

(i) Inclusive class intervals: In this case, values equal to the lower and upper limits of a class are included in the frequency of that same class.

(ii) Exclusive class intervals: In this case, an item equal to either the upper or the lower class limit is excluded from the frequency of that class.

In the case of discrete variables, both exclusive and inclusive class intervals can be used.

In the case of continuous variables, inclusive class intervals are used very often.