What is a class interval? How are the magnitude of the class interval and class limits determined?
Class interval: When the whole range of variable values is classified in some groups in the form of intervals, then each such interval is known as class interval. For example, classifying a group of people according to the same age groups. Here, the class intervals are:
15 - 19 years, 20 - 24 years, 25 - 29 years and so on.
Magnitude of the Class interval: The difference between the upper and lower boundaries of a class interval is called the magnitude of the class interval.
Class Limits: The numerical figures used to specify the lower and upper limits of a 'class interval' are called class limits. For example, if the class interval is 15 - 19 years, the lower class limit is 15 and the upper limit is 19 in this case.