Remember: When the class intervals are fixed such that the upper limit of one class is the lower limit of the next class, the classes are called exclusive classes, whereas in the inclusive classes the upper limit is included in the class itself. The classes of types 15–19, 20 –24, 25–29, etc., are inclusive classes. Hence, statement 1 is incorrect The classes of types 15–20, 20 –25, 25–30, etc., are exclusive classes. Hence, statement 2 is incorrect