In statistics, when dealing with grouped data, the terms class boundary and class limit are often used, and while they may seem similar, they serve different purposes.
Class limit refers to the range of values that define a class or group within a frequency distribution. Each class has an upper limit and a lower limit. For example, in the class interval 10-20, ’10’ is the lower class limit, and ’20’ is the upper class limit. These limits are inclusive in terms of counting values in that class.
On the other hand, class boundaries are the values that separate one class from another and ensure there is no overlap. Class boundaries are typically determined by taking the average of the upper limit of one class and the lower limit of the next class. In our previous example, if we have a class interval of 10-20 and the next class is 20-30, the class boundaries would be 9.5 and 20.5. This means that the class boundaries are set to include all data points without ambiguity.
To summarize, the main difference is that class limits define the range of values for a specific class, while class boundaries provide a precise division between adjacent classes to eliminate overlaps. Understanding both concepts is essential for accurately analyzing and interpreting grouped data.