Distinguish between inclusive and exclusive methods of grouping data?

Inclusive methods of grouping data include the endpoints of each class interval, meaning that the upper boundary of one interval is included in that interval and the lower boundary of the next. For example, an interval of 10-20 would include both 10 and 20. In contrast, exclusive methods do not include the upper boundary of one interval in that interval; thus, the same interval would be represented as 10-20, where 20 is considered part of the next interval. This distinction affects how data is categorized and analyzed, particularly in statistical calculations.