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# How to Find Class Boundaries in Statistics?

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In Statistics class can be defined as a Set of data or members or we can also say that class is collection of different objects. These classes can be divided based on different parameters. Example of a class is a set of students who are alumni with same year of graduation. In mathematical terms it is an interval in frequency distribution. There can be different number of classes containing different data. Now we will see how to find class boundaries in statistics.
Class boundaries can be defined as average of upper limit of a class and lower limit of next class.
So formula for finding class boundaries is given by (upper limit of a class + lower limit of next class) / 2.
We can find class boundaries with help of steps shown below:
Find upper limit of class that is last value of class.
Find lower limit of next class that is first value of next class.
Find the average of upper limit of class and lower limit of next class.
Result we get after step 3 is the class boundary.
Lets take an example to understand the concept of class boundaries.
Suppose we have four classes i.e. 0 – 5, 6 – 10, 10 – 15, 15 – 20.
Then class boundaries for above classes can be found as shown below:
For class 0 – 5, upper limit = 5, lower limit of next class = 6.
Class boundary = (upper limit of a class + lower limit of next class) / 2.
= $\frac{(5 + 6)}{2}$ = 5.5.
Similarly we can find class boundaries for other classes.